With regards to professional sports, there isn't any real way to "fix" that, short of promoting a new sport that makes use of the natural physical endowments of women, compared to men.
What I mean to say is that nobody "decides" what sports are popular. Even when women play the same sport as men, such as the WNBA, it's not as popular because men are, on average, and at the pinnacle, simply faster, stronger, and tougher than women, on average. That makes the games more exciting and more fun to watch. Since women identify with women, they are more likely to want to watch the women's games, but there aren't enough women who are that interested in the sport to counterbalance the men who aren't interested in watching.
In the sports that are currently popular involve lots of hard hitting action, and men are simply better, on average, at providing that sort of entertainment.
There exist leagues for women for pretty much every sport out there, at the weekender and amateur levels, in most places. It's just that the economy of sports doesn't support professional level coverage without professional level crowd draw.
There's professional figure skating, dance, gymnastics, etc, that could be expanded beyond the current format, perhaps, but that isn't confrontational enough for most people.
Danika Patrick is doing good things for women in racing, maybe more women will get into that. And I think the Tampa Bay Lightning had a female Goalie when they first started up. There are female fighters in the MMA world, not UFC yet, but Elite XC and I think Pride feature female competitors. The wrestling Divas are doing pretty good, but that's more entertainment than competition.
I guess what I'm getting at is that there is and has been plenty of opportunity, but nobody has done well enough yet for it to really "catch", and it's hard for women to compete in sports that are designed around men's natural physical advantages. Some rare women are capable of playing at that level, but not enough.
Unless someone invests a pile of money into creating and promoting some new sporting venue that becomes popular beyond anyone's wildest imaginings, I don't see women's sports coming anywhere near as successful as NFL, MLB, etc.