Evolution’s Rainbow

I had some extreme ambivalence about this book. Ultimately, it is an extremely ambitious book with a broad scope, aiming to be one of the major pieces of gender and sex literature for several groups, including biologists, educators, trans, intersex/people with differences in sexual development and genderqueer individuals, queer groups debating whether to include trans issues, politicians and doctors. So the fact that it was a little weak on some of these fronts was to be expected and cannot be said to detract from the overall groundbreaking nature of the book.

The book is organized into three parts: gender, sex and sexual orientation in animal organisms; gender, sex and sexual orientation in people, and finally, the history of gender variation in human societies.

Not surprisingly, given that Dr. Roughgarden is an organismal biologist, the first part is by far the strongest. And it's not just strong relative to the rest of the book, it is truly a superlative work. It explores first the biologic definition of sex and speculates about species in which there could be more than two sexes on the basis of diversity of gamete size in several known species. She then goes on to discuss hemaphroditism (sequential and simultaneous.) I didn't find much of this novel, probably because I consider myself somewhat of an amateur ichthyologist, and most of these early examples involved reef creatures I was already familiar with, but Roughgarden still presents it in a way that it is compelling and flows well with the earlier portion of the book on sex. The absolute best part of the book is about gender in animal species: Roughgarden explores several species (mainly birds, lizards, fish and insects, initially) looking at the diversity of gender roles and family structures that exist in different species. She speculates as to the evolutionary advantages of having a diversity of gender roles, in that it allows for rapid response to shifting environmental factors, and argues that it provides an increased chance of offspring survival in other cases. Finally, looking at mostly primates, Roughgarden discusses same sex relationships in the animal kingdom, again arguing that same sex relationships fill an evolutionary niche, by helping negotiate alliances that increase the chance of offspring survival. Importantly, in all of this, Roughgarden is very clear that exploration of gender, sex and sexual orientation variance in animals is important for our understanding of diversity, but she does NOT argue that LGBT people should be supported BECAUSE of the occurrence of parallel traits in animals, but rather just because it's moral to support them. She explicitly states that much of animal behavior should not be accepted in humans and much of human behavior that is valuable is not found in animals. I think warning people of how easy the naturalistic fallacy would be here and actively discouraging her readers from failing for it was both courageous and intellectually honest.

So ultimately, I have only two gripes with this entire first part, and both are completely semantic. One is that she continually refers to her idea of the “genial gene” (genetic traits that have evolved to encourage interorganism cooperation so as to encourage survival of offspring and thereby increase individual reproductive fitness) as being in conflict with the Dawkinsian idea of the “selfish gene” (genes evolve to increase survival of themselves.) These are not at all in conflict. They are both consistent with evolutionary biology as it is currently understood and the “selfish gene” hypothesis supports the evolution of genetic traits that are “altruistic” in behavior if that supports the expansion of the gene in the population. The second is that Roughgarden insists on referring to genetic diversity as a “genetic rainbow.” In the middle of a narrative that is otherwise talking about gametes, alleles, and other complex biologic topics, all of a sudden using “rainbow” as a scientific noun is jarring and undermines Roughgarden's credibility. I know that she wanted to increase readability, but honestly, anyone who gets through this first section has the reading comprehension to understand the word “diversity.”

The next two parts are rockier. I had the hardest problem with the middle part, in which Roughgarden makes several diversions. One is to criticize American medicine for overpathologizing people especially with genetic conditions. She makes an argument that if a trait has a certain population frequency, it must not be that pathologic. This argument is technically true: for a given allele frequency, there is a bound on the effect on reproductive fitness, given a limited de novo rate of mutation. However, this argument ignores the possibility of heterozygote advantage, given that many (most?) of the conditions that she argues therefore must be beneficial or neutral are autosomal recessive. In addition, the discussion of reproductive fitness is not a value judgement – one of the conditions that she agrees must be the most deleterious to reproductive fitness, complete androgen insensitivity, is a condition that I would strongly argue should not be pathologized: people (usually women) with complete AIS require the use of advanced reproductive technology to have biologically gonads, because they have sperm-producing gonads, female genitalia and usually identify as women. That's a huge reproductive hit, but an otherwise normal person. On the other hand, she argues that salt-wasting congenital adrenal hyperplasia is overpathologized, and as a medical geneticist, I'm going to defend my right to pathologize genetic conditions that kill infants. She then extends herself to genetic conditions in general (not just differences in sexual development) and generalizes that the risks of genetic engineering, as well as the ethical risks of selective reproductive technology outweigh any benefit to treating these patients, whom she claims are overpathologized. Again, I'm sensitive, because this is my job, which I have a doctorate and extensive postdoctorate training in, but I see children die because of their “genetic trait, which is not necessarily a disease” and it is extremely sad. I have helped couples select embryos that do not carry the genetic condition that their sibling died of and I'm not sorry.
Dr. Roughgarden recommends at the end that the FDA certify whether a condition is a disease before a doctor can treat it, and I think this argument really showcases ignorance of the medical bureaucracy and the issues involved: FDA approval is an extremely slow process, even now, sticking to Food and Drugs, which there are clear processes for. The number of just human genetic diseases is in the thousands. She herself uses examples of allelic conditions where at one end there is clear disease and the other end is more a variant of normal (such as AIS and CAH above.) I daily see patients with alleles that have never before been reported. If I needed FDA approval to see a patient in my clinic based on their individual allele, it would probably take a decade for each patient to be approved! I wish that Dr. Roughgarden had been given an opportunity to attend a medical genetics clinic. I think modern medical geneticist are by and large thoughtful and avoid unnecessary pathologizing. I suspect that this is simply a case where Dr. Roughgarden, brilliant as she clearly is from the first chapter, is not as up to date on medical genetics. To be clear: I agree with her completely that patients with DSDs were historically overpathologized and were victimized by poorly considered operative strategies, and I understand that given her expertise in gender and sex she would be suspicious of the rest of the field.

I liked other parts of this chapter: Dr. Roughgarden thoroughly debunks the idea that there are substantial gender differences in humans. She then reviews the gender differences that have been reported and puts them into context for the reader. I wished she would have gone even further into rejecting the idea that there is scientific scaffolding for meaningful gender dimorphism in humans, but she does discuss this a little in part three, where she explores several cultures that have had a third gender as a category for either people with DSDs or people who are trans. This part is a little rocky, because at times, she imposes her categories on the narratives of the people she is summarizing. Although she is careful, she sometimes uses pronouns or nouns that are gendered differently than what the person used, claiming that the person would have identified as fe/male had that society allowed it. On the whole, I found it relatively interesting to look at the historic and geographic span that gender variation has occupied and encouraging to look at societies that were largely accepting of gender variation.