A very small pet peeve

I've seen/heard this argument a whole lot lately, and it's beginning to bug me. The argument goes: There is no necessary and sufficient condition for being (biologically) a woman. Some women have a Y chromosome, some women lack a vagina, some women lack a uterus, some women lack breasts, some women begin life with male genitals, and some women go on to acquire male secondary sex characteristics and/or genitals. Furthermore, we typically classify people into sexes based on secondary sex characteristics and social characteristics, not based on chromosomal structure or reproductive organs. Therefore, (and here's where I get off the boat) there is no legitimate biological category 'woman'.

I can certainly see why someone would find this persuasive. (I can also see why someone would be motivated to find it persuasive, which is a bit different.) Still, I think it's based on a misguided view of concepts in general, and a misunderstanding scientific concepts in particular. The premises are all right, but they don't entail the conclusion. Even in science, few categories have neat edges, and especially in science, many categories are invisible to the naked eye.

'Species' is a good example of a category that's both unobservable and fuzzy. People don't realize it, but there's no simple and easy criterion that two things must fulfill in order to belong to the same species. Here are some possible ways of cashing out the idea of 'species':

1. Two creatures are members of the same species just in case they are cross-fertile.
2. Two creatures are members of the same species just in case they have the same phenotype.
3. Two creatures are members of the same species just in case they have similar DNA.

These are all important to the idea of species, but none of them captures it exactly. 1 is too broad, since there are inter-species hybrids, many of which are fertile (e.g., dog-wolf and dog-coyote hybrids, or the famous wholphin that recently had a baby). There's another problem with 1.: some creatures are cross-fertile only under extraordinary circumstances. If two creatures have different breeding seasons in the wild, but produce fertile offspring under special laboratory conditions, are they cross-fertile or not? There's an even bigger problem when we consider organisms that reproduce (only) asexually. How can two amoebas be cross-fertile?* So 1 seems like an inadequate definition of species.

Like 1, 2 is too broad: there are creatures that share a phenotype but seem to be different species. For instance, there are several species of mosquitos that look extremely similar, and until recently were classified as the same species based on phenotype. Some of these species breed only in salt water. Others breed in fresh water and and can reproduce without a blood meal; still others breed in fresh water and require a blood meal to reproduce. In addition to being too broad (because of the mosquito example), 2 is too narrow: a chihuahua and a great Dane don't share a phenotype, but they're of the same species. And how broadly are we supposed to define 'same phenotype' anyway? It seems hard to define it in a way that will lump different breeds of dog together, but keep different species of mosquito apart. Finally, what about creatures that exhibit dramatic sexual dimorphism, like many kinds of spiders, or even drastic sexual polymorphism**, like ants and bees?

As for 3, how similar is 'similar'? Can haploid, diploid, and polyploid organisms all belong to the same species? Do mules constitute a different species from horses and donkeys? What about bacteria, which go around absorbing chunks of each other's genetic code? Do they change species over time?

So I don't think there's any neat way of defining 'species'. Nor are species observable: two of the concepts three concepts that I've associated with species--cross fertility and DNA--are invisible to the naked eye. Although the differences between species are kind of messy, however, I don't think you should throw out your field guide just yet. In general, cross-fertility, phenotype, and DNA tend to go (roughly) together. And vague and unobservable 'species' is, it's still a good guide to many important things. It tells you which plants are edible and which will poison you, what role organisms play in their ecosystems, and when putting two organisms together is likely to get you babies. Just because it's not a perfect classificatory system doesn't mean it's useless. Otherwise, we'd have to throw out classificatory systems altogether.***

One last word on species: even if most organisms belong to a species, not everything has to. Maybe mules, tigons, and wholphins don't. People should recognize the limitations of their categories.

To bring the analogy home, chromosomal makeup, reproductive equipment, secondary sexual characteristics, and perceived gender come apart to some degree. But more often than not, they tend to go together, and that fact is useful for anyone who wants to understand and manipulate their environment and/or themselves.

Still, not everyone necessarily belongs to a sex. There are people who fit sex categories only imperfectly, if at all. People need to be mindful of that, and not force others into categories that don't necessarily fit.

Please note that although I believe in biological sex, I think gender stereotypes are generally bullshit. The reality or close-enough-to-reality of sex doesn't give anyone a license to be sexist. My take-home message here is that feminism and biology are not at odds. Feminists can't afford to reject a nuanced view of biology or other sciences, any more than scientists can afford to reject a nuanced view of feminism.

*I bet some smartass is going to come and tell me about sexual reproduction in amoebas now. If so, very cool.

**I'm sure it's not really called that. But can anyone explain to me why worker bees are supposed to be female, rather than just a third sex? This does look like a place where stupid presuppositions get in the way of accuracy.

***Other concepts that we'd have to throw out awfully fast are 'gene', 'color' (as in 'visual color'), 'race', 'and 'class'. This would make it really hard to navigate the world.