I think hockey might be the best sport for a woman to break the professional sports barrier, full-time (as opposed to a Manon Rheume type gimmick). Specifically as a goalie. There the size and strength differences would be mitigated, and a 'somewhat' larger woman of say 5'11, 175lbs would not be out of place, or too small. She would have to have extraordinary reflexes, flexibility and agility, but then so do all goalies.
I've played hockey against women before, and at the lower levels it's not that big a deal. They can generally skate just as good (often better) than most guys, though they tend to have much weaker shots. But unless you're trying to blast one in from the blueline you can work around that too. After a couple of shifts you generally forget that you're playing against a woman. Unless, of course, she starts punching you in the face during a scrum in front of your net, which happened to a friend of mine in a game once. He just stood there letting her punch him in the face because he didn't know what to do - she actually got a penalty for "beating" him up!
