This could be the century when the sexes go their separate ways. Sure, we've hung in there together for about a thousand millenniums so far--through hunting-gathering, agriculture and heavy industry--but what choice did we have? For most of human existence, if you wanted to make a living, raise children or even have a roaring good time now and then, you had to get the cooperation of the other sex.
What's new about the future, and potentially more challenging to our species than Martian colonization or silicon brain implants, is that the partnership between the sexes is becoming entirely voluntary. We...