Gender Variation In Animals, and Evolution’s Rainbow

If the book Biological Exuberance is about gay animals, then Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People is about the full lesbian, gay, bi, transexual, and intersex spectrum.

Joan Roughgarden is an evolutionary biologist at Stanford University, and speaking from her personal experience as a transsexual, she analyzes the staggering variety we see in the animal kingdom. Sometimes too dense for the casual reader, it is nonetheless a fascinating and important book. She’s particularly insightful on the rainbow of gender variations both in animals and humans, proposing myriad new and provocative perspectives.

I love finding out how mind-bending the natural world is. God or Mother Nature or whoever is in charge certainly has a sense of humor and a profound devotion to diversity, and this book is an amazing job of trying to explain how it all works and why.

Finding Nemo, And True Clownish Gender

Clown fish home life

The world’s coral reefs are the greatest producer of diversity on the planet, and that diversity includes gender variation.

In the wonderful Pixar movie Finding Nemo, Nemo’s mother is killed in the first scene. The rest of the movie is about the relationship between the surviving father and son clown fish.

Except that is not what happens for real clown fish. Real clown fish switch genders. As portrayed in the movie, clown fish live in a single anemone in monogamous breeding pairs of one larger female and a smaller male, along with some juveniles. However, in real clown fish lives, if the female dies, the adult male changes into a female, and one of the juveniles becomes an adult male. So… Nemo’s father should have become the larger female, and Nemo should have become his father’s, now wife’s, husband. That certainly would have made a more surprising movie.

I imagine Pixar had some lively meetings talking through the human-like story they wanted to tell using fish who have a very different idea of family building.

The Nature Of People Who Are Intersex

Caster Semenya (Wikimedia Commons)

The first question we ask when a baby is born: is it a boy or girl?

We often consider the male-female binary a core distinction of life, but on the the most basic level of how our bodies are constructed, life isn’t that simple.

The world was shocked by the recent questioning of the gender of a South African track star. Caster Semenya identified as female, and won races across the world. Yet her deep voice and muscular physique lead to questions about her sex. Subsequent tests revealed a complex answer. Semenya has no uterus or ovaries, and has internal testes that produce three times the normal testosterone for a woman. (We all produce both testosterone and estrogen, so it the presence in anybody’s system is just a matter of degree.) Given that we sort athletics into the male/female binary, where should Semenya, who does not fit clearly into either category, run?

Semenya is not alone. A friend of a friend is a 6’5” man with a vagina. Many people have variations of both internal and external sex organs that befuddle labeling, along with varying hormone levels, and even varieties of chromosomes beyond XX and XY. Some women have just one X, referred to as Turner syndrome, and some men are XXY, or Klinefelter syndrome. As many as 1% of us are intersex in some way, and surgeries to “normalize” genital appearance is done in one or two births in 1,000.

It is easy to see how these body variations occur. In his March 1993 Atlantic article on Homosexuality and Biology, Chandler Burr described the sexual development of the fetus:

Human beings of both sexes start out with complete female and male “anlages,” or precursors of the basic interior sexual equipment — vagina, uterus, and fallopian tubes for women, and vas deferens, seminal vesicles, and ejaculatory ducts for men. These packages are called the Mullerian (female) and Wolffian (male) ducts, and are tubes of tissue located in the lower abdomen… At the moment of conception an embryo is given its chromosomal sex, which determines whether it will develop testes or ovaries. In female human beings (as in female rats) the female structures will simply develop, without any help from hormones; the Wolffian duct will shrivel up. The process of becoming male, however, is more complex. Where women need none, men need two kinds of hormones: androgens from the testes to prompt the Wolffian duct into development, and a second substance, called Mullerian inhibiting hormone, to suppress the Mullerian duct and defeminize the male fetus.

We used to view any variation in a child’s genitalia as unacceptable. Babies born intersex had “corrective” surgery as soon as possible, as if cutting off a child’s micropenis and putting the baby in a dress will make it into a girl. Intersex people are now speaking out against this kind of mutilation, saying these actions are based on the discomfort of the parents rather than the best interest of the child. People who are themselves intersex are increasingly asking for acceptance of their physical variations exactly as they are as children, knowing they will sort out the physical and emotional issues in their own personal way as adults.

Are these variation really so shocking? I would think it is obvious to anyone who watches the Olympics or uses locker rooms knows that we vary. As the old joke goes, whoever said everyone was created equal had not seen very many naked people.