Co-Ed Curling
Someone on MetaFilter asked why curling has separate events for men and women. He's being a bit of a dork in the thread, but the question was an interesting one - not so much in the case of 'why is there?' but 'why, in the future, might there not be?' This is what I wrote in response (somewhat edited for spelling, etc):
There are significant historical differences in the men's and women's games. Those factors are, in my opinion, decreasing as years go by, but they still exist. I'd say the two key factors in the decreasing difference are ice conditions and the four rock rule (and its predecessor, the three rock rule).
The improvement in ice conditions (especially arena ice, which was traditionally crap) have made it possible for both men and women to play a finesse game very successfully. For one thing, ice has a lot more curl now than it used to (except in fricking Torino, where it blows), so there's a lot more options in terms of come around shots. Typically, in the past, men played up-weight take-out games, while women were forced into a more finesse style because they couldn't throw the up-weight needed. The finesse style wasn't as workable though, because the ice didn't have the movement it does now. The fact that everybody can now succesfully play a finesse game favours equalization - though it also emphasizes sweeping which pushes things back in favour of the men a little.
The other huge factor in equalization is the introduction of free guard zones rules. Back in the bad old days, curling games made football (that is, soccer) games look like scoring extravaganzas. It wasn't entirely unheard of for 10 ends to go by with no score at all, because the two teams would just pick rocks off until someone fucked up. That sort of game, with lots of up-weight take-outs decidedly favoured the men. But with the advent of four rock rule, where they *can't* take out initial guards, the kind of come around, tick shot, finesse play that women have always favoured is much more important and prominent. See above for how this plays out in terms of equalization.
Strength and conditioning are significant factors. It is a sport, despite the jokes, and as with most sports, men are just more physically built to deal with those aspects. They will always have more options open to them because of the up-weight abilities that they have, and thus will always be at least marginally better than equally skillful women's team.
Combine that with the fact that curling is a *not* a new sport, and has a great deal of history, and you get separate events. I mean, curling was first an Olympic sport in 1924 or so, and has national and international competitions since long before the idea of men and women competing together was seriously considered.
An additional factor that I wouldn't entirely discount, either, is the same sort of thing that face women in the workplace. A lot of great young female curlers get married, have kids and give up competitive curling. As a sport, the demographics skew older than most. The people out there curling aren't 16 year olds or college students. Most Canadian curlers have day jobs (unless you're ultra-elite, it doesn't pay the bills), and they dedicate weekends and vacation to major tournaments. It's tough to do that and raise kids at the same time.