Download TURNING A MAN

TURNING A MAN
by Jared Diamond
Discover Magazine June 1992
BARBARA GREW UP AS AN APPARENTLY NORMAL GIRL ENJOYING A HAPPY
CHILDHOOD. AS HER TEENAGE YEARS APPROACHED, SHE LOOKED FORWARD TO
EXPERIENCING THE SAME SEXUAL DEVELOPMENT SHE SAW IN OLDER GIRLS.
GRADUALLY, HOWEVER, SHE BEGAN TO HAVE A VAGUE SENSE THAT THE EXPECTED
CHANGES WEREN'T HAPPENING IN HER.
BY THE AGE OF 14 SHE WAS REALLY WORRIED: SHE HAD NOT YET MENSTRUATED
AND HER BREASTS SHOWED NO SIGNS OF GROWTH. WHAT SHE DID HAVE WAS A PAIN IN
HER LEFT GROIN THAT EVENTUALLY SUBSIDED, ONLY TO BE REPLACED BY THE
APPEARANCE OF A MASS IN THE LEFT SIDE OF HER LABIA. WITH GROWING SHOCK,
SHE FELT HER VOICE DROPPING, HER FACIAL HAIR GROWING, AND HER CLITORIS
ENLARGING TO BECOME MORE AND MORE LIKE A PENIS.
After Barbara’s sixteenth birthday, her penis developed erections, she
produced ejaculations, and she found herself feeling a sexual interest in
girls. By now she had become convinced that she was really a boy and that
the mysteriously shifting mass within her was in actuality a testis. But
Bar-bara still struggled with the problem of how to present herself to her
parents and friends, before whom she avoided being caught naked. She knew
they had to suspect something. When they found out, would they ridicule
her - or him - as a freak?
Gender constitutes the most fundamental distinction we make among
ourselves, the first question we ask when a baby is born. It establishes
two radically contrasting possibilities and deter-mines how we view
ourselves and how other people view us. In almost all cultures it also
establishes a division between contrasting economic and social roles. To
find one's gender ambiguous or shifting is as cruel a blow as could befall
one's ego. It's as close as any of our children might come to the
nightmare experienced by Gregor Samsa, of Franz Kafka's terrifying story
Metamorphosis. who wakes up one morning to find himself transformed into a
human-size insect.
The vast majority of us are born unmistakably male or female and remain
that way throughout life. We have all the sexual parts appropriate to a
single gender, with no discordant pieces. It is very rare indeed that you
find among humans true hermaphrodites - individuals possessing both male
and female gonads.
However, there are some unfortunate individuals called
pseudohermaphrodites, whose sex presents an ambiguous appearance. At the
births of thousands of babies each year in the United States, the
obstetrician can't pronounce, "It's a girl!" or "It's a boy!" but must
confess, "I'm not sure what it is." Like Barbara, some appear to be born
as girls but develop as boys at puberty. Some have a vagina and female
external organs but lack such internal organs as ovaries and fallopian
tubes; in-stead, they have certain male internal organs, like seminal
vesicles, as well as testes hidden up in the body.
Most of these walking mosaics of sex manage to survive this adversity:
indeed, their stories are moving testimony to humans' ability to cope with
the injustice that can be dealt out by nature. But their stories are also
instructive, for they shed light on a number of basic questions that
concern all of us. Foremost among them are the questions:
What actually determines our gender? How could the mechanisms that
determine something so fundamental go so wrong?
ULTIMATELY of course, our gender is laid down by our genes, which are
bundled together in each cell in 23 pairs of microscopic packages called
chromosomes. The 23 human chromosome pairs can be numbered and
distinguished from one another by consistent differences in appearance For
chromosomes 1 through 22, the two members of the pair appear identical.
Only in the case of chromosome 23, the sex chromosome, do the two
representatives differ, and even then only in men, whose twenty-third
chromosomes are of unequal sizes: a larger X chromosome paired with a
smaller Y chromosome. Women have two paired X chromosomes instead.
What do the sex chromosomes do? Many X chromosome genes specify traits
unrelated to sex, such as the ability to distinguish red and green.
However, the Y chromosome contains genes specifying the development of
testes. Between the fifth and seventh week after fertilization, human
embryos of either sex develop an all-purpose gonad that can later become
either a testis or an ovary. If a Y chromosome is present, that allpurpose gonad will begin to commit itself by the eighth week to becoming a
testis. But if there's no Y chromosome, it waits until the thirteenth week
and then begins developing as an ovary. Thus the natural tendency of our
primordial gonad is to develop as an ovary if nothing intervenes;
something special, a Y chromosome, is required to change it into a testis.
It's tempting to restate this simple fact in emotionally loaded terms.
As developmental biologist Alfred Jost put it, "Becoming a male is a
prolonged, uneasy, and risky venture; it is a kind of struggle against
inherent trends toward femaleness." Chauvinists might hail becoming a man
as heroic, and becoming a woman as the easy fallback position. Conversely,
one might regard womanhood as the natural state of humanity, with men just
a pathological aberration that regrettably must be tolerated as the price
for making more women. I prefer merely to acknowledge that a Y chromosome
switches gonad development from the ovarian path to the testicular path,
and to draw no metaphysical conclu-sions.
BUT THERE'S MORE to a man than testes alone. A penis is among the many
other obvious necessities, just as women need more than ovaries, for
example, it helps to have a vagina. To form the penis, vagina, and other
sex organs, the embryo is endowed with other all-purpose sexual structures besides the primordial gonad. However, unlike the case of the
testes, the development of these structures is not directly specified by
the Y chromosome. Instead, these structures are channeled to-ward male
organs by secretions of the testes themselves, while a lack of testicular
secretions chan-nels them toward female organs.
For example, in the eighth week of gestation the testes begin producing
the hormone testos-terone, some of which gets converted into the closely
related substance dihydrotestosterone, or DHT. Such hormones are called
androgens. DHT goes on to convert some all-purpose embryonic struc-tures
into the glans penis, penis shaft, and scrotum. Those same structures
would otherwise develop into their female equivalents: the clitoris, labia
minora, and labia majora.
Embryos also start out with two sets of ducts, known as the Müllerian
ducts and the Wolffian ducts. In the absence of testes the Wolffian ducts
atrophy, while the Müllerian ducts grow into a fe-male's uterus, fallopian
tubes, and the inner part of the vagina. With testes present, the opposite
happens: androgens produced by the testes stimulate the Wolffian ducts to
grow into a male's semi-nal vesicles, vas deferens, and epididymis. At the
same time, a testicular protein called Müllerian in-hibiting factor does
what its name implies: it prevents the Müllerian ducts from developing
into the internal female organs.
Since a Y chromosome specifies testes, and since the presence or
absence of the testes' se-cretions specifies the remaining male or female
structures, it might seem as if there's no way that we could end up
hermaphrodites. Instead, you might think, a Y chromosome should guarantee
100 per-cent male organs, whereas the lack of a Y chromosome should
guarantee 100 percent female or-gans.
In fact, a long series of further biochemical steps, programmed by
chromosomes other than the sex chromosomes, is required to produce all the
structures other than ovaries or testes. Every step involves the synthesis
of one enzyme, specified by one gene. If any one gene is altered by a
mutation, the enzyme for which it's responsible may be defective or
absent. Thus, an enzyme defect may result in a male pseudohermaphrodite,
defined as someone with one X and one Y chromosome, and hence
intrinsically male, but with a mixture of both male and female structures.
In the pseudohermaphrodite, some male structures continue to develop
normally because they depend on enzymes and hormones that remain normal.
However, male structures dependent on the defective enzyme are either
completely missing or replaced by their female equivalents. This can be
illustrated by a discussion of two types of male pseudohermaphrodite, one
resulting from a defec-tive androgen receptor, the other from a defect in
the enzyme that converts testosterone to DHT.
THE FORMER type looks like a normal woman. Indeed, "she" often conforms
to the male ideal of feminine beauty even more than the average woman does
because her breasts tend to be well developed and her legs long and
graceful. Her complexion is usually flawless and she tends to have the
added height of a man. Hence, cases have turned up repeatedly among female
fashion models.
Since this type of pseudohermaphrodite looks like a normal baby girl at
birth and externally undergoes normal development and puberty, the problem
isn't even likely to be recognized until the adolescent consults a doctor
over her failure to begin menstruating. At that point the doctor discovers
a simple reason for that failure: the patient has no uterus, fallopian
tubes, or upper vagina. Instead, the vagina ends blindly without
connecting to a uterus (although it is generally adequate for intercourse). Further examination reveals testes that are normal except for
being buried in the groin or labia; they secrete normal testosterone and
are programmed by a normal Y chromosome. In other words, the beautiful
model is a male who happens to have a genetically determined biochemical
block in the ability to respond to testosterone.
That block turns out to be in the cell receptor that would normally
bind testosterone and dihy-drotestosterone and thereby enable those
androgens to trigger further steps in the development of male genitals.
Take away that androgen receptor and all you normal male readers might
look like beautiful models, too. Since the pseudohermaphrodites' Y
chromosome is normal, the testes them-selves form normally and produce
normal Müllerian inhibiting factor, which acts as it does in any man to
forestall development of the uterus and fallopian tubes. However, the
process by which the usual male machinery is activated by testosterone is
interrupted. As a result, development of the remaining all-purpose
embryonic sex organs follows the female channel by default: female rather
than male ex-ternal genitalia, atrophy of the Wolffian ducts, and hence no
development of male internal genitalia.
The result, then, is a genetic male who can't become male-in short, a
genetic male whose visible sexual parts are those of a woman. Despite
having a Y chromosome, hidden testes, and nor-mal male testosterone
levels, almost all such people unquestionably view themselves, and are
viewed by others, as women. Most find husbands and marry. Naturally,
without a uterus or ovaries, they can't bear children, but many adopt.
Most are well adjusted to their role as women and show no signs of unusual
emotional stress. In these cases, not only do testes fail to make a man,
but they fail to interfere with much of the happiness available to women
as wives and mothers.
The second type of pseudohermaphrodite is exemplified by the case of
Barbara, with which I began this article. Barbara and dozens of other
similar people suffer from an enzyme defect called 5-alpha-reductase (5AR)
deficiency. Like the pseudohermaphrodites with defective androgen receptors, they are genetically males, with a normal Y chromosome and testes
and normal production of testosterone and Müllerian inhibiting factor.
Because of this inhibiting factor they don't develop a uterus, fallopian
tubes, or the internal part of the vagina. Their external genitals appear
largely female at birth, though they may be somewhat ambiguous and have
some male features; this ambiguity sometimes allows babies with 5AR
deficiency to be recognized at birth. At puberty, however, many of these
children become much more male-like.
A mutation in the gene specifying 5AR yields a more confusing picture
than does androgen receptor deficiency. In the first type of
pseudohermaphrodite that we discussed, the effects of the an-drogens were
blocked completely. But in this second type the influence of only one
androgen, DHT, is affected, while the influence of the other,
testosterone, is exerted normally. This is because the 5AR enzyme normally
converts some testosterone into DHT; an impaired 5AR gene and enzyme mean
less DHT production. Because the two androgens function somewhat
separately, the result is that in 5AR-deficient pseudohermaphrodites,
reproductive organs specified by testosterone are nor-mal and only those
dependent on DHT are abnormal. Ironically, the resulting blend of male and
fe-male traits has helped researchers distinguish the precise
physiological roles played by testosterone and DHT in male development.
Which male traits are normal in 5AR-deficient males and hence
influenced by testosterone? Because these babies are born with testes
(albeit concealed in the groin or labia) and normal male internal organs
(seminal vesicles, vas deferens, and epididymis), we can conclude that the
growth of these structures must be triggered by testosterone secretion
while the fetus is still inside its mother's womb. Hallmarks of adolescent
male development that remain normal include muscle development, growth of
the penis and scrotum, capacity for erections and ejaculation, and lack of
breast develop-ment. These may be influenced by testosterone secretion at
puberty.
At birth, though, these genetic males show numerous female traits.
Their external genitals look much more like a clitoris and labia than a
penis or scrotum. There is a vagina, although it ends as a blind tube.
Inside, the prostate gland is small or absent. The urethra opens not at
the tip of the pe-nis/clitoris but in front of the anus and close to the
vagina (which means that although these pseudo-hermaphrodites are able to
maintain an erection and engage in intercourse, the urethra's location
ensures that the ejaculate emerges from the orifice between the legs
rather than from the penis and doesn't enter the female partner's vagina).
These features make it reasonable to assume that the normal molding of the
prostate and male external genitals probably depends on DHT-which is deficient in these pseudohermaphrodites-rather than on testosterone.
At puberty these pseudohermaphrodites experience less-than-normal
growth of the beard and body hair, while later on the baldness that
gradually comes to characterize most older men fails to develop. These
traits of normal men, then, are likely to depend on postnatal effects of
DHT
Because the 5AR gene is not on the sex chromosomes, both males and
females donate a copy of it to their offspring. A single normal copy of
the gene, inherited from either parent, suffices to generate enough 5AR
enzyme for normal male development. Only if a male fetus inherits a
defective gene from both his mother and his father will he develop as a
pseudohermaphrodite with 5AR deficiency. Therefore, most known examples
are clusters of related cases in remote, isolated third world villages,
where marriages between close relatives are common and children can
inherit many of the same genes from both parents.
For example, one such cluster was discovered in a rural, inbred village
that until 1960 had no paved road to the outside world. I'll refer to it
as Xanadu to protect the villagers' privacy. In Xanadu, physicians have
identified a total of 38 pseudohermaphrodites, all descended on at least
one side from the same now-deceased woman and many of them traceable to
that woman through both their mother and father. Evidently, that lady had
a single copy of the mutant gene, which she passed on to many of her
numerous descendants. Eventually there were enough such descendants so
that some marriages within the village began to involve partners who both
carried the mutant gene, thus making it increasingly likely that their
children would develop as pseudo-hermaphrodites. In fact, of the origi-nal
woman's great-grandchildren, one turned out to be a pseudohermaphrodite;
among her great-great-grandchildren, there were 6; her great-great-greatgrandchildren, 14; and her great-great-great-great-grandchildren, 17.
HOW DO such 5AR-deficient pseudo-hermaphrodites cope with the
Kafkaesque metamorpho-sis that their genes force upon them? Not
surprisingly, there is a wide spectrum of outcomes, de-pending on the
biological endowment of each person, the response of the immediate family,
and the response of the society. I'll illustrate this spectrum with
examples from Xanadu and another society I'll call the Sambia, one of
which found it much harder to come to terms with pseudohermaplirodites
than did the other.
For several decades in Xanadu, all pseudohermaphrodites were identified
at birth as girls and were raised unquestioningly as girls. But by 1950
there had been enough cases of baby "girls" who became adolescent boys
that the villagers began paying closer attention to newborn babies'
genitals. Since the late 1950s most pseudohermaphrodites have been
recognized at birth or in childhood and raised as boys. Among the older
pseudohermaphrodites, though, there were still 18 who had been reared as
girls.
On reaching adulthood, only one of those 18 maintained "her" identity
as a woman. As a teen-ager she married a man (who deserted her after a
year), and then began to work as a housemaid and wear false breasts. The
other 17 gradually became convinced of their masculinity by the changes in
their bodies during adolescence. They were at first hesitant to come out
as men because they feared ridicule, and indeed they did become the
targets of jokes. Their families were initially as-tounded and confused
but eventually accepted them as boys. Fifteen of them married, and a few
ac-quired stepchildren through their wives' former marriages. Gender roles
within these 15 unions are traditional, with the male pseudohermaphrodite
working at a typical man's job involving heavy labor, while the woman
keeps house, cares for a garden, and looks after any previous children
that she may have had.
IT IS STRIKING how rapidly the Xanadu pseudohermaphrodites readjusted
their gender role. The sex they were reared as had little effect on the
age at which they passed the signposts of male adolescence, such as when
they first experienced morning erections, wet dreams, masturbation, and
sexual intercourse. For example, the ages for first sexual intercourse
prove to be very close for pseudohermaphrodites raised as boys (15-17),
pseudohermaphrodites raised as girls and switching to a male role during
adolescence (15-18), and normal boys in the same village (14-16).
Some authorities on human psychosexual development maintain that we
acquire our gender identity as young children. According to this view that
identity is firmly fixed by the age of four. Among Xanadu
pseudohermaphiodites, though, kids who viewed themselves unquestioningly
as girls throughout most of childhood came to view themselves as men after
adolescence and to dress, work, and have sex accordingly. That's not to
claim that the switch was easy or that it left them emotionally unscarred.
However, the switch was more complete and took place over less resistance
from family and friends than has been the case with another group of
pseudohermaphrodites whom we shall now consider.
The next section of this article is fairly graphic, but not necessary
for your understanding of the principles involved, so if you want to read
it, come talk to me.
Given the nature of Sambia society we can barely be surprised at its
difficulties in accommo-dating pseudohermaphrodites comfortably. Indeed,
gender ambiguity provokes nervous squirming in almost all of us DISCOVER
authors and readers, Olympic testing committees, the general public, and
even physicians. For example, it's extremely upsetting to a physician to
have to break the news to parents, "We can't figure out the sex of your
child." We view gender as so fundamental and nor-mally unambiguous - and
we’re so uncomfortable even about normal sexual issues.
THE PSEUDOHERMAPHRODITES themselves are made to feel like pariahs,
mocked to their faces and whispered about behind their backs. Nearly 40
years after graduating high school, I still cringe to recall how my
schoolmates stared and laughed at one unhappy classmate with ambiguous
genitals whenever we took showers in the locker room. His life must have
been daily torture. Nowa-days there is much sympathy for patients with
other types of genetic defects, but not yet for pseudo-hermaphrodites. The
harsh fact is that gender ambiguity does arise occasionally, and it
presents itself in a wide range of forms. I hope that as our scientific
knowledge about pseudohermaphrodites advances, they will meet with the
sympathy they deserve.
QUESTIONS ON TURNING A MAN:
ANSWER THESE QUESTIONS IN PARAGRAPH FORM ON A SEPARATE SHEET OF
PAPER
1. Imagine yourself going through puberty and changing from the sex you
were raised as to the opposite sex.
a) What kind of feelings do you think you would have experienced?
b) How would your family and friends have reacted?
c) Given the option do you think you would stay with your “new” sex or
opt for surgery to reverse the changes?
2.
Using the information in the article, describe the normal development
of the human reproductive system.
3.
Briefly describe the difference between the two types of
pseudohermaphrodites.
Bonus points if you can accurately differentiate between the two using an
explanation of the hormones and genes involved.