Man and Woman, Part IV: The Sex Chemicals

from the frontiers of sex and science, an unprecedented playboy series on what makes man man and woman woman

Günter Dörner is head of The Institute for Experimental Endocrinology (hormone research) at Humboldt University in East Berlin. Since the early Sixties, he-- like other scientists--has been working to find a way into the connections between motivation, brain and behavior. And like other scientists, he has concentrated on the different sexual motivation and behavior of male and female.

When the scientific community began to understand that it is the hypothalamus--an important structure in the brain--that ultimately controls the output of the hormones and the different patterns of male and female reproduction, Dörner was quick to find in the hypothalamus of rats different male and female sex centers. These centers, formed under the influence of the sex hormones at a very early stage of development, were responsible, he believed, for male and female sexual behavior. And Dörner showed that if the rats didn't get enough of their appropriate sex hormone during development, then something would go wrong with the centers and with later sexual behavior. Adult rats would behave sexually like members of the opposite sex--they would become "homosexuals."

From that, Dörner argued that sexual behavior must also be stamped by the hormones into the human brain while it is still developing in the womb and that primary human homosexual behavior must be the result of a sexual stamping that has given the brain the wrong gender. He quotes a study in which male homosexuals obsessively attracted to children were "cured" by an operation on their brains' supposed female sex center. And he himself has performed a series of experiments that show, he believes, that both male and female homosexuality are caused by the prenatal effect on the brain of either too little or too much of the main male sex hormone--testosterone.

Last fall, Dörner attended a high-level conference of hormone and brain specialists in Cambridge, England--one of the rare occasions on which he has left his laboratory for the West. And we flew to Cambridge to meet him and to talk firsthand with this shock-haired, twinkling, forthright man who sparks controversy wherever he goes. What he told us gets right to the cutting edge of hormone research--and to the bigger subject of the differences between men and women in behavior and ability.

"You see," says Dörner, speaking fluent, accented English during our first, rushed conversation, in an empty student's room at Cambridge University, "I think people know quite well what we call the activational effects of the sex hormones, the way they control the reproductive cycle in women, and so on. And they know that at puberty, the sex hormones influence hair, breast and muscle growth and attraction to the opposite sex. They know, too, what happens when various hormones are taken by athletes and transsexuals and so on. But what they don't know very clearly is what we call the organizational effects of these hormones.

"These effects are written into the organism long before puberty--in fact, at various stages of the fetus' development in the womb. And they affect not only the form and shape that the body will come to have but also the way it will respond to hormonal influences at puberty.

"They also affect--quite profoundly--the structure and chemistry of the brain. They lay the foundations for a range of behaviors that will characterize the organism as male or female after birth. We have found--in humans, rats, guinea pigs and other animals--that sex hormones operating on the brain during critical periods of early development can produce a variety of masculine or feminine sexual and social behaviors, regardless of the genetic sex.

"There's no doubt," Dörner says, "that this theory is controversial. And it's true that we don't know everything we'd like to know about these hormones. But my theory is completely consistent with what we do know from both animals and humans. We know that in fetal males, the highest level of testosterone coincides with the period when the hypothalamus is organized to control the later expression of male sexual behavior. And it's completely consistent to believe that this stamping is affected--both here and in other parts of the brain where these hormones have been found--when the hormones are present in abnormal quantities."

Dörner is late for the conference's official banquet. "We'll talk later," he says. But we continue to talk as we hurry through a medieval quadrangle in the direction of the dining hall. Then: "Look," he says, stopping, the light catching his rimmed spectacles, "it's very, very hard to test my theory reliably in humans. For that, we would have to monitor a large number of pregnancies, constantly check hormone levels and then follow the behavior of the children born for up to 20 or 25 years. How does one do that? I don't know." He shrugs. "So, in the meantime, we just have to make do with the available evidence. From clinical patients and from animals. This evidence, which is now coming at a very fast rate from laboratories all over the world," he says before disappearing into the darkness, "supports me."

&2022;

Nothing is really simple about the sex hormones. They are, in fact, among the most mysterious molecules in nature. They're produced in different quantities by both men and women--though they're only a tiny chemical step away from one another. Their levels in the body change all the time--monthly, daily, perhaps even hourly. And they act not only on the body but also on the brain. As Dörner--whom we will come back to later--says, much is known about the role they play in the body in the control of the female reproductive cycle and the maintenance of pregnancy. Much is known about the effects they have on how men and women look: Give a male-to-female transsexual estrogens (the family of sex hormones related to estradiol) and he will often grow breasts and add fat at hips and thighs; give a female-to-male transsexual androgens (the family of hormones related to testosterone) and she will often grow an enlarged clitoris and gain facial hair, a deeper voice and a masculine musculature. Those are features induced by the sex hormones--in normal males and females--at puberty.

Very little, however, has been known until recently about the way the sex hormones affect the brain--not how we look and function as men and women but who we are as different genders with different sex-typical behaviors, skills and abilities. And that is what this installment of Man and Woman is ail about. It is a dispatch from several new fronts of science. As you have already seen, its subject matter is extremely controversial, and it may be profoundly unsettling for both the men and the women who read it. For it suggests that men are the expendable, deviant sex and that women are genetically protected only for the purpose of motherhood. It suggests that we are much more like other animals in nature than we care to believe. And it suggests that not only is the length of our life directed in some way by the sex hormones (see box, page 238) but so-- before birth--is much that is important about our personalities as men and women: our gender identity, our sexual behavior, our tastes, our special abilities and even our choice of career. It's a bumpy ride, this installment in the story of men and women. It concerns the accidents of nature and the mistakes of man: homosexuals and housewives, rats and monkeys, tomboys and jocks. And it needs a constantly changing focus. Hang on.

&2022;

Focus One. At the Beginning: Nature's Point of View

Picture to yourself the minuscule cell that worked and divided to become the person you are today. It is an instant after conception, and your mother's egg has just been penetrated by one of the 350 million of your father's swimming sperm. The cell being formed now has in it two millionths of a millionth of an ounce of DNA--all the information necessary to produce a 50-trillion-cell creature with your particular nose, feet, eye color and crooked grin. This information is arranged in 46 chromosomes--23 provided by your mother's egg and 23 the gift of your father's sperm. They are now in the process of matching up into pairs.

Each of these chromosomes is a pack of genetic cards, the result of a more or less random shuffling of genes from each of your parents' matched pairs of chromosomes. And so the 50 percent you have inherited from each is organized by chance. There are, however, two exceptions to this rule. And those are two chromosomes that are relatively well protected and passed on without shuffling-- the sex chromosomes. An X chromosome is automatically passed on to the original cell--and to you--by your mother's egg. And either another X or a Y is handed down to you by your father's sperm. If you are XX as you read this, you are a woman; if XY, then a man. And that's all the difference there is.

Not a lot, you might think. And genetically speaking, you would be right. What, after all, is one chromosome--the X or Y inherited from your father-- against 45 others, 44 of which have been provided in equal ratio by both a male and a female, by both mother and father? Given that who we are is a complicated business, then it must be scattered over those other 45 chromosomes as well.

That is the line taken, quite understandably, by a good many people. One chromosome, they say, may be responsible for the way our bodies look and function. But how on earth can it be responsible for any other claimed differences between men and women? In the toys we're supposed to want to play with? In the different abilities we're supposed to have? In the sexual roles we're called on to fill; in the sexual tastes it's considered right for us to display? We must, they say, be more alike at birth than unalike--more bisexual. It must be only after birth, they say, that sex differences are forced upon us.

A perfectly reasonable point of view on the face of it. If you shuffle traits from both parents, as nature has chosen to do, then you're bound to end up with potentially bisexual creatures. It's a problem. One that nature herself had to face--and to solve.

Let's personalize nature for a moment. Her problem is this. Once she's made a commitment to sex and the sexes (see Man and Woman, Part Two: The Sexual Deal, Playboy, February), she wants to preserve it and to preserve all the advantages the new gene shuffling involves--the highly various offspring it makes possible. But at the same time, she wants to make sure that physically and behaviorally the two sexes remain distinct from each other and--very important--attractive to each other. She wants mating, sexual reproduction and a sexual division of labor to continue. She can't afford confused signals or a unisex.

So what can she do? Well, there are two things: She can abandon gene shuffling for a large number of the chromosomes. Or she can be more economical-- she can put the X and Y chromosomes in charge of an auxiliary system that will intervene after conception in the way the 44 other chromosomes are expressed.

That is, in fact, what nature did. Instead of giving up any of the gene-shuffling advantages, she created, early in evolution, a mechanism that monitors the way the chromosomes' genes are expressed in the male and female body and brain. She invented a process that could reach within the same cells and switch them in either a masculine or a feminine direction. She invented the sex hormones. It is the sex hormones that are responsible for the different abilities of male and female rats. It is the sex hormones that are responsible for the different postures of male and female dogs when they urinate. And it is the sex hormones that, in humans, are responsible for differences in bones, muscles, (continued on page 226)Man and Woman(continued from page 146) kidneys, liver, pelvis size, hair growth, breasts and sexual organs. And a lot more besides. They are responsible for the cushion of fat a woman carries against the coming of lean times and for the sudden attraction that springs between male and female at puberty. They are responsible for a whole range of sex-typical risks, drives and behaviors.

&2022;

Focus Two. Hormones and the Sexes:

The View from Outside

When scientists have looked from the outside at the effects of the sex hormones on the brain and behavior--which is hard to do--these are some of the disputed bits and pieces of evidence they have found: Basses have more testosterone and less estradiol than tenors--and they also have more active sex lives. Rapists and exhibitionists have higher testosterone levels than is normal; alcoholics have lower. Tall male executives have sex more frequently than short ones, and their level of testosterone may go up both before and after sex. Old men produce more estradiol and less active testosterone than young ones. And in one part of the Northern Hemisphere, levels of testosterone are highest around September, when most children are conceived. The poet was too general. For in this particular part of the world, a young man's fancy turns to thoughts of love not in spring but in late summer.

Scientists have found the beginnings of a connection, in other words, between sexual drive and testosterone. Give large doses of it to a female-to-male transsexual and even her libido goes up. There's also a connection in men among the Y chromosome, testosterone and another brain-behavior--aggression. Just as Japanese fighting fish can be made extra-mean-spirited by the experimental addition of an extra Y chromosome, so men born with an extra Y chromosome--an accident of nature--tend to be more impulsive, more antisocial and, perhaps, more aggressive than normal males. That is likely to be brought about by testosterone. Hockey players who respond aggressively to threat have been found to have higher levels of testosterone than usual. And prisoners with long, florid histories of violent crime seem to have higher levels than the normal prison population.

It makes sense, perhaps, that sex drive, aggression and testosterone should come together in men in one evolutionary package. For males in nature usually have to fight to mate. The package is not, though, a particularly well-protected one, and it can easily take on a distorted, antisocial shape. Young males--whose levels of testosterone are highest--commit almost all the violent crimes, and many of them are sex-related.

There are other distortions as well. For instance, many more men combine sexual deviance and aggression than do women. Aside from their tendencies toward rape and exhibitionism, men commonly practice things virtually unknown in women: homosexual incest, pedophilia (sex with children) and homosexual sadism and masochism. One of the few ways these things and the fantasies they give rise to can be treated-- short of brain surgery or castration--is with drugs that block the actions of testosterone.

So much for men. The picture for women is much less clear, partly because they're hormonally more complicated, partly because they suffer fewer genetic defects than men and partly because-- since women are less deviant--science is less often called on to treat them. Women's troubles, if any, seem to have to do with mood rather than anything else. The premenstrual "blues," for example, are probably caused by an altered balance of estradiol and progesterone-- visions of which are given in the various forms of the birth-control pill. And these two sex hormones are almost cer-tainly somewhere behind women's proneness to depression. They are likely, too, to be at the root of the lack of aggression in the so-called weaker sex. Given externally, progesterone and its relatives induce calmness. And estradiol and its relatives seem to promote a sense of well-being.

In women, then--though there is much less evidence than for men--the evolutionary package that comes with the sex hormones and the two X chromosomes also comes with a sensitivity to mood, an evenness of temperament and a general lack of volatility. Males born with two X chromosomes as well as a Y are unusually passive, and male-to-female transsexuals given large doses of estrogen are less arousable and less sexually aggressive. This packaging, again, would make sense. Individual females are important to nature as the main investors in the continuation of the species, so she's careful to protect them hormonally against impulse, hostility and a misplaced sexual drive. Individual males she cares much less about. Given their small investment, any of them will do.

&2022;

Focus Three. Men Versus Women:

The Struggle Inside

Men are expendable--there's no way around it. And life is something of a struggle for them. They're victimized by nature's careless packaging and by her all-too-plain willingness, with males, to cut her losses if something goes wrong.

This is the view from the inside-- from the womb itself. For it is in the womb that the Y chromosome is first expressed and the Y-linked sex hormones start to shape male behavior. It is in the womb that the struggle to be male begins, a struggle that begins for one simple but devastating reason: The natural form of the human is female and the male has to be hormonally superimposed on her. Like it or not, males are converted females with a high casualty rate. They have to do complicated battle to establish themselves in the world.

Picture to yourself again the fertilized egg that became who you are. It is somewhere in the second month of pregnancy and you are about 15 millimeters from top to bottom. Up to this point, there's no difference between a male and a female embryo--all the male and female parts exist in both in a primitive form. At about this stage, though, the male and the female begin to take separate paths. If you're to be female, the gonads, the two collections of germ cells, now begin to develop into ovaries. The male ducts disintegrate--and the female ducts thicken and become the womb, the Fallopian tubes and the upper two thirds of the vagina.

If you're to be male, however, your Y chromosome interferes with this process. It forces development in another direction. It causes, scientists believe, production of a substance called H-Y antigen, which sticks to the surface of the ovarian cells and forms them into testicles. And the testicles then put out two sex hormones in sequence. One absorbs the female parts that would have become the womb, and so on. And the other-- testosterone--protects the male ducts, thickens the spermatic cord and. through a third hormone called dihydrotestos-terone, promotes the formation of the male external genitals.

What is interesting, though, about this male sequence is that a number of things can go wrong with it--things that always push the development of the male back in a female direction. Strip the H-Y antigen from the cells of a developing testicle in a test tube and the testicle will re-form itself into an ovary. Remove the testicles from the fetus of an experimental animal and it will return to the path toward femaleness. This refeminizing can be found in humans, too. A number of genetic human males who make it through to life are born female, either internally or externally or both. The reason is either that they couldn't produce H-Y antigen or one of the three hormones it sets in motion or that they were insensitive to one or more of them. In other words, the target cells for these substances weren't equipped with the receptors--or special receiving stations-- that are necessary for them to be effective. The sex hormones could not enter the cells and start the machinery that switches their genes in the required masculine direction.

So much for the differences between the male and female sexual and reproductive organs. The important thing to remember is that--in the male's case, at any rate--genetic sex is no guarantee of anything. It is the hormones produced by the testicles that do the work. What the hormones produced by the ovaries do is, again, much less clear.

&2022;

Focus Four. Meanwhile, in Another Part of the Forest

You may not like rats. But they are important to science. And in order to investigate just what effect the sex hormones have on the brain, and on sex-typical activities, drives and behaviors in humans, science has to start with the rat. Rats are cheap. They reproduce quickly. They are easy to manipulate. And, in a number of recently discovered ways, they are eerily like humans. Young male rats, for example--like human male infants--are more playful, more rough-and-tumble than young female rats. Adult males, too, have different abilities from adult females. Females are better at certain kinds of learning and they're more adventurous in the open. But males are better at figuring out mazes--just as human males are. That requires visual and spatial skills that are likely to be located in the rat's right hemisphere--as it is. again, in humans. Marian Diamond of the University of California at Berkeley has recently found that the surface of the female rat's left hemisphere is slightly thicker than the male's, while the back of the male's right hemisphere is significantly thicker than the female's. That is exactly what one would expect to find in humans, though no one has found it. For in humans, females have greater language skills-- in the left hemisphere. And males have greater visual and spatial skills--at the back of the right hemisphere.

That may not seem like much-- especially to a snooty lord of creation like yourself. But for our purposes, it means a great deal. For all of these abilities and attributes in rats can be altered, in a masculine or feminine direction, by the presence or absence of hormones during the rats' so-called critical period--the stage of development during which the sex hormones organize maleness and femaleness. This critical period in rats is a short one and its time span stretches from before to after birth. In humans, of course, the critical period is much longer. But it is probably all before birth.

Roger Gorski of the University of California at Los Angeles has done pioneering work on the effects on the brain of the sex hormones during that critical period. "We've known for a long time," he says when we visit his laboratory at UCLA, "that if we give male hormones to female rats during this period, they will neither ovulate nor behave sexually like normal adult females. If, as adults, they're later given testosterone, they'll behave sexually as males. The reverse is also true. Deprive a male rat of male hormones and later give it estrogen, and it will behave sexually like a female. It will proffer itself and arch its back in the female posture we call lordosis.

"These changes, I originally thought, were probably due to some altered responsiveness of the system to hormones. I thought it unlikely that any structural differences would be found in the brains of male and female rats that might account for them. But then various things happened. First, Günter Dörner found differences in the nuclear size of nerve cells in the hypothalamus. Then, a British and an American group found differences in the interconnections between nerve cells. And then, Fernando Notte-bohm of The Rockefeller University found major differences in the brains of songbirds. That really set us looking."

In 1976, Nottebohm and Arthur Arnold--now a colleague of Gorski's at UCLA--announced that they'd found two gaggles of nerve cells in the brains of canaries that were three and four times larger in the male than in the female. It's the male canary, not the female, that sings. Nottebohm and Arnold showed that these centers were responsible for the male song, which is both learned and left-hemisphere dominant, as is human language. They also showed that the sex hormones were dramatically involved in the formation of these centers and in song itself. For when adult female canaries were given testosterone, not only did their two centers grow, they also started--falteringly--to sing.

Here, then, was the first real connection linking the sex hormones, behavior and brain structure. And it led Nottebohm--a courtly, soft-spoken man--to predict two things: first, that whenever the male and female of a species differ in the development of a skill, a correspondingly greater or smaller amount of brain space will be given over to the neural organization of that skill; and second, that that skill and the brain space allotted to it will be dictated by the sex hormones.

That was enough for Gorski and his co-workers. They quickly went hunting for a similar gaggle of cells--or nucleus--in an area of the rat hypothalamus that they knew to be involved in the regulation of reproduction. It wasn't long before they found what they were after. "We, too, discovered a nucleus," says Gorski. "We call it the sexually dimorphic nucleus, and it is larger--five to seven times larger--in the male than it is in the female. We couldn't alter this difference by manipulating hormone levels in adulthood. But we could do so by manipulating them during the rat's critical period, at around the time of birth. Females that we masculinized during this time had a much larger nucleus than normal females. And castrated males had a much smaller nucleus than normal males. The size of the nucleus, in other words--just like adult sexual behavior--depends on the hormonal environment to which the brain is exposed during the critical period. And this seems to be true even when it's taken out of the brain. Dominique Toran-Allerand, working with fetal mice at Columbia University, has put the general region that contains this center into culture in the lab. She's found that it develops differently depending on whether or not masculinizing hormones are present.

"The genetic sex of the tissue, like the genetic sex of our animals," Gorski says, echoing Dörner, "is immaterial. It is the sex hormones that are important."

Whether the sex hormones and Gorski's nucleus are, between them, responsible for the other sex-typical behaviors of male and female rats is not yet known. But more and more connections are now being made between the sex hormones, brain and behavior. Bruce McEwen of The Rockefeller University has discovered sex-hormone receptors during the critical period in precisely those areas of rat brain that are thought to organize differences in behavior other than sexual--maze running, avoidance learning and so on. And what Gorski has found in rats and Nottebohm and Arnold have found in birds, a tall, mustached scientist named Robert Goy has begun to find in a species much closer to us: rhesus monkeys.

When you walk down the corridors of the Regional Primate Research Center at the University of Wisconsin in Madison, the first thing that strikes you is that rhesus monkeys are indeed a lot like ourselves. Their features are in the right places. They're outgoing and energetic. And they're socially complex--playing with one another, dominating one another and all too ready to demote or ostracize a member of the troop if he or she doesn't come up to snuff. The infants are especially attractive. Housed on the fifth floor in groups with five or six mothers, the young monkeys careen around their cages noisily, leaping from foothold to handhold, stopping only to romp briefly together and mount both one another and their mothers in a sociable pantomime of sex.

It took Goy five years to find a way of housing his rhesus monkeys in socially unstressful conditions like the ones they're in today--conditions more or less like those of the wild, in which their behavior would be natural. Even so, he has found it virtually impossible to study the effects of sex hormones on adult sexual behavior, as Gorski has done in rats and Goy himself has done in guinea pigs. "There are too many social variables that we know little about and would have to take into account," he says.

What he has been able to study, though, is the effects of hormones on various sorts of sex-typical behavior. "We've done some work on dominance, for example," he says in his office across the road from the center. "Males usually occupy the dominant position in a troop. But we've shown that females whose mothers were given testosterone during pregnancy are much more likely to be the dominant members in a mixed troop, as adults, than are other females. This effect of prenatal testosterone--I'm just now beginning to work on estrogen effects--can also be seen in the way infants and juveniles interact. And that's what I've mainly been working on.

"There are four main ways in which young male rhesuses differ in their behavior from females. They initiate play more often. They roughhouse more often. They mount their peers--of both sexes--more often. And they mount their mothers more often than females do.

"We can, however, produce a male-typical frequency of all these behaviors in young females if we give their pregnant mothers thigh injections of testosterone or dihydrotestosterone for various periods of time during the critical period of development--which is before birth. These females will play rough and so on. And many of them will be born with masculinized genitalia-- there's clearly a critical prenatal hormonal period for that.

"But there's also a critical period-- much longer and much harder to define--for the acquisition of these sex-specific behaviors under the influence of the hormones. And what's so interesting is that they don't all come in one bundle. We can separate them. We can give androgen injections for quite a short period of time, for example, and females will mount their mothers much more often--but not their peers. Peer mounting, in turn, can be separated from play behavior. And finally, the mounting of male vs. female peers can also be separated out. Incredibly, we've exposed male fetuses to additional male hormones for a really short time in early pregnancy, and we've recently found that they'll mount only female peers. No other male behavior is affected.

"This suggests--in these primates, at any rate--that the individual bits and pieces of behavior that make up masculinity are separately controlled by the sex hormones over time. Masculinization, in other words, is a slow, iffy, complicated, more-or-less process; you get tooth-and-claw males and you get less masculine ones. This doesn't seem to be true of feminization. Our altered females may be masculinized, but they are not defeminized. In fact, there are no feminine traits that we can identity and then suppress by exposing the fetus to hormones. And furthermore, there are no feminine behaviors that are not common to both sexes. Males--and our altered females--are, in other words, simply females who've had a male pattern superimposed on them. Their femaleness remains--much, much better protected by nature than maleness. In males, nature can afford a wide variation. But females bear children, and nature needs every one of them she can get."

&2022;

Focus Five. Men, Women and the Sex

Hormones: Coming Full Circle

How can one argue from rats, birds and monkeys to humans? "One can't," say some scientists. "One can," others say cautiously--believing, above all, in the economy of nature. They point to the little we know about humans from the accidents of nature and the mistakes of man. They point, inevitably, to C.A.H. women.

With C.A.H. women, we come full circle, to take the results of work done with animals back into the human brain, as Günter Dörner has done. C.A.H. stands for congenital adrenal hyperplasia, a disorder of the adrenal glands, which are responsible for our reactions to stress, among other things. In individuals with C.A.H., something has gone wrong--starting in the womb-- with production of the adrenal cortex' main hormone, cortisol. Instead, during the human critical period, as the fetus is developing, large quantities of testosterone are produced.

In boys that has little obvious effect, but in girls it masculinizes--to one degree or another--their external genitals, as in Goy's monkeys. These days, the condition is usually recognized in early infancy. The baby girls are surgically altered--if necessary--and are thereafter given cortisone-replacement treatment.

Their behavior, though, has already been pushed in a masculine direction-- and that isn't alterable by surgery or cortisone treatment, however soon after birth those are applied. The male hormone, in other words, has had its effect on behavior before birth, as in Goy's monkeys. And after birth, the effect can be measured. According to a series of studies begun by John Money of Johns Hopkins University and Anke A. Ehrhardt, now at Columbia University and New York State Psychiatric Institute, C.A.H. girls are more tomboyish than their female peers. They're athletic and highly energetic. They prefer boys as playmates. And they are quick to involve themselves in organized, competitive group sports. In Money's words, "They join in boys' neighborhood football, baseball and/or basketball games, often as the only girl."

Some of this behavior has been explained by saying that C.A.H. girls expend energy in a way that has been masculinized--males, and maybe C.A.H. females, have bigger lungs and hearts and a higher oxygen consumption than normal females. But there are other differences that can't be explained this way: C.A.H. girls prefer toy guns and cars to dolls; they prefer functional to traditionally feminine clothing: they prefer playing cowboys and Indians to playing house and career-rehearsal games to fantasizing about marriage and infant care. They show little enthusiasm for babies and little interest in stereotypical girls' activities. Their puberty is often later than other girls' though it is made normal because of the cortisone treatment. And they don't become as quickly attracted to the idea of romance and dating with the opposite sex. Later in life, C.A.H. women seem to be attracted, in some degree, to other women, just as they would be if they were normal males. As a group, they may show a higher incidence than is statistically usual of bisexuality and even homosexuality--if not in practice then, at any rate, in erotic fancy.

All of that is vividly reminiscent not only of Goy's monkeys but also of Gorski's rats. But: "Look," says Ehrhardt in the cafeteria of the New York State Psychiatric Institute, "we have to be extremely cautious about this. I find the jump that Günter Dörner makes from animals to humans absolutely unacceptable. These things, after all, are just trends. They're not found in every individual. And in the case of bisexuality and what may be bisexual and homosexual impulses, we don't even know if these are any more common in C.A.H. women than in the rest of the population. We don't know enough. You see, this is so hard for people to understand. They think in terms of a hard-and-fast distinction between what is biologically determined and what is socially determined--nature us, nurture. And these things must interact. How one behaves, after all, depends a great deal on whether or not one's behavior is frowned on. Well, homosexuality and bisexuality aren't as frowned on as they once were. And so we find these inclinations in C.A.H. women, just as we might find them in any sampling of women as a whole. As for tomboyism--well, yes, it's true that C.A.H. girls are significantly more tomboyish than a population of girls matched for age, background and so on. But one, tomboyism is perfectly socially acceptable in this society. And two. not every C.A.H. girl is a tomboy. It is not biologically guaranteed."

Ehrhardt, professor of clinical psychology at Columbia, is a very careful scientist. A precise, smiling woman in her 40s, she's well aware of the controversy that surrounds her field. She's quick to maintain the importance of learning in humans, and she discountenances any idea that our sexual and social behaviors can be dictated by the hormonal environment in the womb.

Nevertheless, for more than a decade now, Ehrhardt has been investigating-- most recently with Heino Meyer-Bahl-burg--just what effects this environment may have. Besides looking at C.A.H. individuals, she has also studied an entirely different population--children whose mothers were given hormones to maintain their pregnancies. Some of those hormones were estrogens-- hormones related to estradiol--given either in a natural form or in a synthetic version such as diethylstilbestrol (DES). And some belonged to a group of hormones called progestogens. These hormones were, again, either natural (animal derived) or synthetic (laboratory made). Some were progesterone-based and some were androgen-based--closely related to testosterone.

As far as researchers can tell, the children born after their mothers were treated with those substances differ from controls only in the circulating sex hormones they were exposed to in the womb. Ehrhardt and Meyer-Bahlburg and groups headed by June Reinisch of Rutgers University and Richard Green of the State University of New York at Stony Brook, among others, have tried to tease out their effects on later behavior. The case is clearest for the progestogens. Girls exposed to androgen-based progestogens seem very similar to C.A.H. girls--more tomboyish and energetic than usual and often born with subtly masculinized genitals. Boys also seem more energetic and aggressive than their peers--as C.A.H. boys do.

The reverse, however, seems to be true of progesterone-based progestogens, whether given alone or in combination with estrogens. These hormones seem to have a slight demasculinizing effect. Boys exposed to them appear as a group to be less aggressive and assertive than their peers. They show poorer athletic coordination and what one study calls "lowered masculine interests." The picture is similar in girls. They're also less energetic than usual and less verbally aggressive. They express a preference for female--rather than male--friends. And they show an increased interest in feminine clothing and hairdos, cosmetics and children.

&2022;

What does that mean for us as men and women? It may mean, as Goy says that "sex hormones operating on the brain organize not merely sexual behavior but also social demeanor and orientation to social problems and their solutions." It may mean, as Ehrhardt says cautiously, that "a sort of pretuning takes place."

Or it may mean something more. It may mean that there really are such things as stereotypical male and female attributes--amplified by society, to be sure, but organized in the brain before birth. They may include, in women, an instinctual drive toward motherhood. And they may include female intuition, male visual and spatial skill and all the other abilities we discussed in the last installment, The Brain as Sex Organ. All of us--differently "masculine," differently "feminine," differently ambitious and intuitive and gifted--may be products not only of the environment but also of the subtle interplay, in the womb, between hormones and the developing brain. If that is so, then we have little hope of imposing on ourselves through education and upbringing any absolute equality of the sexes--any more than we can impose any absolute equality on our sexual organs. All we can do is try to understand how nature works, as science tries to do. And understand the mechanisms by which she has tried to keep men and women as different from--and necessary to--each other as possible.

We may also have to rethink our whole attitude toward homosexuality. The day after our first Cambridge meeting with Dörner, we met him at the conference proper to talk with him about his presumption that homosexuals are born and not made.

"Well," he says, "I saw in rats that they could be made homosexual if deprived of testosterone during the critical period of brain differentiation. And I had the idea that human male homosexuals might also have feminized brains as the result--perhaps--of stress in their mothers. Stress causes the production of substances in the adrenal glands that depress testosterone levels in the male fetus. In my laboratory, we've tested the effect this might have in three separate ways. First, we subjected rat mothers to stress and showed that their male offspring had lower testosterone levels at birth and exhibited homosexual behavior in adulthood--this has been confirmed by two studies in America, two studies that I know of. We then checked the population records to see if more human male homosexuals were born during the stressful period of World War II than were born either before or after it. And we found that this was so. At this point, we gave a number of primary male homosexuals an injection of estrogen, arguing that if their brain was indeed feminized, then it would respond as if to a signal from a nonexistent ovary--with a surge of ovulation-inducing hormone. This is what happened. And it did not happen in heterosexual or bisexual men.

"As a result of this," he says patiently. aware of the people around him who do not agree with him, "and as a result of studies done in my laboratory going back to 1964, I am forced to conclude that male homosexuality is the result of a feminization of the hypothalamus, activated--as far as sexual behavior is concerned--at puberty. I also believe that a similar but reverse process has occurred in lesbians and female-to-male transsexuals. A number of studies have shown that they have abnormal levels-- at least in part--of testosterone and estradiol and a body build that is more masculine than usual."

In late 1981, three scientists associated with the Alfred C. Kinsey Institute for Sex Research at Indiana University published a report that supports Dörner's conviction. The report, the result of a major long-term study of male and female homosexuals, announced that no psychological or environmental variables could be found to account for human homosexuality. Instead, said the researchers: "Homosexuality may arise from a biological precursor that parents cannot control."

Ehrhardt is still not impressed. "I think Dörner has too much riding on his theory," she says. "The studies he refers to are inadequate. And until there is a series of well-designed, well-controlled studies on humans, I will remain intensely skeptical of the view that learning and the environment play only a small role in who people are and how they behave."

Gorski, however, isn't so sure. "I think," he says carefully, "in the work Dörner's doing, he's taking a great step forward. And he could give us a solid answer as to whether or not there's a dependence on hormones in human sexual behavior. I think the verdict's not in yet. But what he's saying is extraordinarily provocative at every level. You know, for example, that women in our society live longer than men, though it's still not clear why. Well, Dörner says that female rats also live longer and that male rats deprived of male hormones during their critical period live the same length of time as females.

"Well...."