The Riddle of Gender

gender identity or sexual orientation had changed at all as a result of the things I had learned and the people I had met over the past few years. My answer was no. I am hardwired as a heterosexual woman, and I am comfortable with that identity; it feels authentic. However, I no longer view my sexual orientation and gender identity as “normal,” generic, or “regular.” Instead, I see that my particular expression of gender and sexuality are unique to me. Straight people, like gay or transgendered people, have complex and multifaceted gender identities. My sense of what it is to be a woman, for example, is quite different from that of Laura Bush or Venus Williams or Condoleezza Rice, or the other women on my block. All of us are natal women, but our sense of ourselves as women, and the way we express our gender, varies from person to person. There are similarities, it’s true, but the range of gender expression within the categories “man” and “woman” seems to vary nearly as much as it does between them. Prior to writing this book, I did not see that variation. Now I do, and I am grateful to those who enabled me to see the world of gender through their eyes, and consequently expanded my range of vision.

With that new perspective, I have come to view gender less as a riddle that should be solved and more as a collage, which we each assemble in our own fashion. Nature provides the canvas, and on that canvas we assemble scraps of meaning from family, religion, science, friends, and the media—a kind of surrealist montage that, like children’s art, is a natural expression of being, so natural that we forget that it is art. Rather than insisting on the primacy of either nature or culture as the source of gender differences, perhaps we now need to recognize that both play a role and that neither explanation makes sense without the other. Nature may provide the architecture of gender, but culture does the decorating. If gender identity is, as seems increasingly certain, hardwired into the brain at birth, and if the way we choose to express our sense of ourselves as gendered beings is dependent on cultural norms, shouldn’t culture follow nature’s lead and celebrate variety? Difference can be, as Susan Stryker points out, “a real source of pleasure,” if only we can overcome our ancient suspicion of diversity. In an era in which Americans are fighting and dying purportedly to free other people, perhaps we might take this one small step toward freeing ourselves by finally outlawing discrimination based on gender expression. What is freedom, after all, if it is not the freedom to be one’s self?

TWO YEARS LATER… Afterword to the Anchor Books Edition

Oh, those perverse fruit flies!

Butch female fruit flies seducing femme ones with the time-honored drosophila courting rituals—tapping the chosen lady on the foreleg, singing to her, and vibrating one wing. Girlish male fruit flies gathered on a food plate forming boy on boy chains, like some kind of Fire Island conga line. What could possibly incite such behavior? Have the fruit flies launched their own Stonewall rebellion—casting off the chains of fruit fly heteronormativity, buzzing with newfound “we’re here, we’re queer, get used to it” pride?

Not exactly.

The gender-queer fruit flies are instead the result of a rather elegant scientific experiment. Ebru Demir and Barry J. Dickson of the Institute of Molecular Biotechnology of the Austrian Academy of Sciences genetically manipulated male and female drosophila—splicing a single neuronal gene, fru—in order to determine whether or not a complex innate behavior like courting could be controlled by a single gene. The answer, in fruit flies at least, is yes.

Among wild-type fruit flies, males court only females and females don’t court at all. The female instead responds to male overtures with her own stereotyped courtship behavior, slowing down in flight and opening her vagina to permit penetration. These courtship rituals are known to be tied to the fru gene, which is spliced differently in males and females. Males with naturally occurring variants of fru have previously been observed to be somewhat unsuccessful in their courting— the fruit fly equivalent of the forty-year-old virgin. Building on this earlier research, Demir and Dickson hypothesized that fru might be a behavior “switch” gene, capable of regulating courtship behavior in the same way that other genes dictate reproductive anatomy. To test this idea, they spliced the gene in the female direction in anatomically male fruit flies, and in the male direction in anatomically female fruit flies.

The result? Sexual anarchy.

Males courted other males, females courted other females, and most astoundingly, when the gender-queer females and gender-queer males— that had been further manipulated to produce female pheromones— were placed in the drosophila equivalent of a singles bar, the females courted the males. It was Cabaret in a jar!

In the sober language of science, Demir and Dickson describe the effects of their experiment in a June 2005 paper published in the prestigious journal Cell.

“Forcing female splicing in the male results in a loss of male courtship behavior and orientation, confirming that male specific splicing of fru is indeed essential for male behavior. More dramatically, females in which fru is spliced in the male mode behave as if they were males: they court other females. Thus, male-specific splicing of fru is both necessary and sufficient to specify male courtship behavior and sexual orientation. A complex innate behavior is thus specified by the innate of a single gene.”

So what, some people might say. Fruit flies aren’t human beings, and just because tweaking a single gene turns a fruit fly community into West Hollywood doesn’t mean that human sexual orientation and gender identity are biologically based. True enough, although drosophila are one of the most popular model systems used by scientists to study genetics and much has been learned from the manipulation of the fruit fly genome. But just to satisfy those who don’t see the relevance of fruit fly genetics to human behavior, let’s turn to some studies in other species more like us, fellow mammals. Mice, for example.

Around the time I was finishing the research for this book, researchers at UCLA discovered that testosterone might not be quite the all-powerful force scientists had assumed when it comes to prenatal sexual differentiation. Throughout this book I have repeated the central dogma of sex research, that maleness is the result of the surge of testosterone midway through the second month of pregnancy. Before the newly formed testicles begin flooding the developing embryo with testosterone, the embryo is androgynous; without that all-important gush of testosterone, it will develop “by default” in the female direction. I mentioned that many female biologists object to this notion of female being the “default” sex, and point out that even if we don’t know exactly what causes an embryo to develop in the female direction, something must be happening. It turns out that they may be right.

Eric Vilain, chief of medical genetics at UCLA, has used DNA microarray analysis to blow a giant hole in the prevailing theory that steroid hormones produced by the gonads are responsible for sex differences in neural and behavioral development. By chopping up embryonic mouse brains, purifying and amplifying their DNA, and measuring the expression of various proteins, Vilain and colleagues identified over fifty genes expressed differently in the brains of male and female mouse embryos before the gonads begin producing any hormones at all.

As the researchers pointed out in an October 2003 paper published in Molecular Brain Research, their results “suggest that there are functional differences between male and female brains which occur independently from hormonal influence. Moreover, these differentially expressed genes are good candidates for a role in brain sexual differentiation and sexual behavior.”

Vilain’s findings attracted a good deal of attention in the media, as did the gender-queer fruit fly study. But unlike Demir and Dickinson, the fruit fly researchers, Vilain didn’t hesitate to connect the dots between mouse brains and human ones. Vilain is a clinician as well as a researcher, and has long worked with intersex children and their families. The knowledge he has gleaned from his work in both the lab and the clinic have convinced him that defining maleness and femaleness from a biological standpoint is a very complex undertaking. “There is no one biological parameter that clearly defines sex,” he says. Nonetheless, his research has shown that the sexual differentiation of the brain begins very early in development, much earlier than was previously assumed, and is at least partially driven by genetics. This understanding has made him an advocate not only for intersexed people, but also for transsexual people. Legal definitions of sex, he says, “are arbitrary and should not impede the freedom of individuals.” Moreover, “significant minorities of individuals are left out of simple civil rights because they don’t fit