Genetics and Gender?
Human Genetics at UCLA
In looking for information to enrich discussion on issues of gender and feminism in one of the courses I teach, I stumbled onto a fascinating website titled Rediscovering Biology that featured a lengthly interview with an expert, a Parisian working at UCLA, Eric Vilain, on the "Biology of Sex and Gender," and the site is so interesting and informative about sexual characteristics, gender identity, and genetics that I've excerpted below, albeit heavily edited by me:
Sex determination is appealing to everyone because . . . . [o]ne of the first characteristics of a human being at birth is . . . boy or girl . . . . The field of sex determination[, however,] is very poorly understood . . . . We know a handful of genes that makes boys become boys and girls to become girls[,] but we know that we're missing a very, very large piece of this puzzle . . . . [such as] why . . . a number of babies would be born intersex . . . . What we know even less is how our brain becomes either more of the masculinized brain or more of the feminized brain . . . . [As for the body,] you can look at [it] with a different perspective[,] which is the makeup of the gonads, whether they're testes or ovaries . . . . We know[, however, that] there are individuals who have ovaries yet they can be XY and conversely . . . have testes and be XX . . . . [A]nother way of looking at [sexual determination] . . . is gender identity. It's one's own perception of one's sex[,] . . . how people feel . . . they are, either male or female . . . . You can have individuals who are fully masculinized, have a penis, have two testicles, they're XY, they have levels of testosterone of the majority of males, yet they feel . . . they belong to the [female] body and in their mind . . . are female . . . . When the sex chromosomes were discovered, it was immediately obvious that males and females were different at the chromosomal level. Females were XX; males were XY. Then the immediate question was: Well, what makes a male a male and a female a female? . . . . One [view] is it's the number of X chromosomes that makes you either male or female and females have two X chromosomes; males have only one. This mechanism is probably the most frequent in the animal kingdom . . . . [But there is the] Androgen Insensitivities Syndrome[,] . . . the inability for androgens -- that is essentially testosterone -- to bind to their receptor. In the Androgen Insensitivities Syndromes, the individuals are typically XY. They have a Y chromosome. They typically have two normally functioning testicles which do produce male hormones, in particular high levels of testosterone, but the testosterone cannot bind to its receptor[, which] . . . makes the external appearance of these individuals to be fully female. They do not have penis. They do have what appears to be a normal vagina and they look [like a] normal female at birth . . . . We [also] know that, there are a number of babies born who are male -- they have two testes and penis -- and yet they do not have a Y chromosome. We started to decipher the molecular mechanisms that lead to this situation and we now know that there [are] a few other genes that can sometimes mimic the action of the genes in the Y chromosome. So the Y chromosome is not this single force that pushes the whole male sex determination pathway . . . . The idea is in instead of having a simplistic mechanism by which you have pro-male genes going all the way to make a male, in fact there is a solid balance between pro-male genes and anti-male genes and if there is a little too much of anti-male genes, there may be a female born and if there is a little too much of pro-male genes then there will be a male born . . . . The pathway [to male or female] is made of a complex network of genes that interact with each other at the molecular level and these interactions depend highly on the dose of each of these genes. So the end result is a subtle balance between a number of genes, most of them still unknown unfortunately that lead to either the making of a male or the making of a female . . . . We know a number of things in sex determination. We know a handful of genes. We know a little bit how they work. We unfortunately don't know how to explain the majority of our patients, who are either intersex or with a complete sex reversal. We can understand what's happening in the molecular level in only about 30% of the cases and that's not very much . . . . Knowing that you're a boy or you're a girl is something that's unique to humans. This is what we call "gender identity" and we don't know how this happens. We don't know why suddenly at a certain age, and rather early actually, about 3, 4, 5 years of age, we just know that we're either boys or girls . . . . How do we know . . . ? I have no idea. I don't think anyone has any idea. I would love to know. We're trying to work on some biological determinance of gender, to try to understand what happens in our brain . . . . But that probably will not even tell us how we know at the time we knew it . . . . Studying gender is complicated: first because there is no animal model for it. You have to study humans. One way to study gender is by looking at individuals who don't feel right in their own gender. They have what we call "Gender Dysphoria." They're unhappy about their gender. Some of them may become transsexuals. They actually perform surgery because they're so intensely unhappy about the gender that was attributed to them that they feel the need to change using surgical tools . . . . Hormones have always been thought as the unique or major factor influencing the development of a male or female brain. We now know that hormones cannot explain everything in the making of a brain, whether it's masculine or a feminine brain. But we don't know really what the other factors are . . . . [S]ome of these factors may be genetic. Maybe pieces of the Y chromosome are important at some level in the brain['s] sexual differentiation. Maybe some environmental factors are also important: there are compounds in the environment that are hormone-like, they're estrogen-like for instance, that might play a role in this. These are purely speculative arguments, but those are the kind of things that we are trying to decipher . . . . Sexual orientation is an independent parameter from gender identity . . . . What we know about the mechanisms of gender identity is extremely poor. What we know about the mechanisms of sexual orientation is a little better but it's not clearly understood. It probably is a mixture of a number of factors -- social, environmental, genetic . . . . [We also have to understand intersex.] . . . . Intersex is an intermediate sexual phenotype. This means that this is a state of being in-between what's commonly accepted as male or female at all levels, that is an anatomical level, gonadal level, and brain level, and behavioral level . . . . Complete sex reversal corresponds to the extreme end of the intersex spectrum, where apparently there is no ambiguity of the genitalia at birth, but yet there is a intermediate state, at some level which is either the genetic level or the hormonal level or the brain level. But at birth sex reversal doesn't show. At birth phenotypically they look either male or female. It's only later on during their lives because they usually cannot go through normal puberty, that we find out that they had some intermediate state in terms of either their genetic makeup or their hormonal makeup . . . . The big dream for me and the big challenge in fact, is to understand the mechanisms of gender identity. This is really the big enigma and to me it's also the most important aspect of sex determination to understand because . . . out of all the definitions of sex, gender is the most important. In fact it's how people feel that is important, regardless of what they look like, of what their levels of hormones are, or what their face or genitalia look like. It's what they feel within themselves. That's what's important. And to understand what make[s] gender identity happen at some point in a human life is absolutely fascinating and extremely complicated to study but that's certainly the next challenge in the research in sex determination.This might seem like a rather long excerpt, but the original piece is so much longer, and also in interview format, that I simply had to radically cut it and leave out most of the original text, but those readers interested in more can go to the link and read the entire fascinating interview.
Dr. Vilain's English is sometimes a bit awkward, but his explanations are usually very clear and tend to support Camille Paglia's advice, namely, that Feminists need to learn more biology . . .