This is also, of course, a gender norm. It’s a socially constructed model for what bodies “should” be like. The ONLY defence I’ve seen of it coming from the “scientific” transphobes is “well, teleological language is common in biology.” True - but this theory cannot be expressed without it.

Spoilers: this is because the theory is a teleological one. Some “GCs” will own up to this, even enthusiastically: Bogardus thinks teleology in biology is great, and that we should have more of it. But he’s a tradcath who’s big into Aristotle - he’s not one of the atheist (pseudo)-“skeptics.”

Teleological descriptions in biology are mostly just a quirk of language anyway - when a *real* biologist says 'an eye is for seeing', they mean it in a 'a system's purpose is what it does' way (which obviously makes a trans person's body the same sex/gender as their mind, by the same token)