The one thing that hasn't been mentioned is that overwhelmingly professional sports and mass media outlets (TV, radio, magazines etc) are owned by Men. Given the prevalent attitudes in this thread, is it any wonder that calender shoots, sexy posters and skimpier clothing than their male counterparts is part of the marketing package for women's sports? They are trying to market female athletes to a market comprised of Men ... those posters and outfits aren't for the ladies, guys.
The decision to participate is not simply one of choice either. You participate in the sexually based marketing or, in many cases, you don't participate in the sport. Or at least you participate with much less support, funding etc.
Beach volleyball is a great example. What athlete in their right mind would voluntarily choose to wear a tiny bikini while participating in a sand sport instead of compression shorts etc? If you don't want to wear the teeny-tiny bikini in order to satisfy the male viewership, you don't play beach volleyball at a high level. Many of the men, on the other hand, even wear tank tops with their beach shorts.
Perhaps one of the reasons that the WNBA is not so popular is that, unless I've missed it, they have eschewed this sort of sexual based marketing to focus on the sport instead. TV viewership suffers, but if the NY Liberty game I attended in NYC is anything to go on, live attendance is just fine. And the throngs of young girls getting autographs after the game was a great thing to see.
Women's tennis, while it benefits from the (archaic tradition) of short tennis skirts is actually a more tactical game than Mens ... a lot of my male friends are rather rabid tennis fans, and many prefer the wome's game over the men's as the lack of raw power actually makes for more interesting and prolonged exchanges.
In my country, the bars are just as packed for the ladies international hockey games as they are for the mens, and every little girl can decide to play hockey (not ringette!) if she wishes, and easily find supportive teams and programs. Though it's kind of different perhaps, there isn't the sort of parity with amateur football in the US, is there?
Perhaps what we are looking at here is simply another example of American cultural politics lagging behind much of the rest of the world (Canada, Western Europe).
I know this is going to be taken the wrong way, but I've been thinking about it off and on all night. It's sad to think that some of the attitudes in this thread can persist in a nation (s) that are currently embroiled in wars in two countries in which our brave troops are dying in an effort that is at least partially directed at providing measures of freedom and equality to women. Women who in turn are being assassinated at an alarming rate whenever and wherever they try to take up the mantle of political and cultural inclusion in Afghanistan (for example). In Canada at least, our involvement in Afghanistan (two more dead soldiers this week) is presented as an effort toward extending security and human rights. Let's try that at home too, hmmm?