Not just biologists and sociologists, but pretty much all of academia. As a college student in the 1990s it was my understanding this distinction came about fro

Not just biologists and sociologists, but pretty much all of academia. As a college student in the 1990s it was my understanding this distinction came about from 2nd wave feminism in the '60s and '70s, but since then I've come to learn that they goes back even further, into the 19th century at least. Moreover, in the past decade a large segment of the left has been actively pushing back against these distinctions and attempting to essentialize (i.e. root in biology) normative gender behaviors. In the eyes of some trans activists essentializing gender norms would reduce anti-trans prejudice. I personally think it's misguided and goes too far, but it does reveal some flaws in the logic of the dichotomy. Some normative gender behaviors undoubtedly are rooted in biology, notwithstanding individual variation. But all such dichotomies are flawed--either intrinsically, or because of how they frame the relevant questions; it's the nature of the simplifications we humans make, and must make, to impose order on the natural world. I haven't seen any good alternatives to the sex/gender dichotomy, and I fail to see how anything constructive can come about from tearing it down.