Put aside Simone de Beauvoir's famous dictum, "One is not born a woman but rather becomes one." Science suggests otherwise, and it's driving a whole new view of who and what we are. Males and females, it turns out, are different from the moment of conception, and the difference shows itself in every system of body and brain.
It's safe to talk about sex differences again. Of course, it's the oldest story in the world. And the newest. But for a while it was also the most treacherous. Now it may be the most urgent. The next stage of progress against disorders as disabling as depression and heart disease rests on cracking the binary code of biology. Most common conditions are marked by pronounced gender differences in incidence or appearance.
That's the thing about science: Given time, it wins out over political correctness.
(Global warming extremists, take note)