About 20 or so years ago an all womens health club in LA was sued by a man for discrimination and the case never got anywhere. I believe Gloria Allred was en voled on one side or the other. As an aside, my wife goes to Curves, which is basically an aerobics club for older women, and one of their appeals to potential members is that since there are no men allowed as members women can feel free to exercise and not worry that some man is going intimidate them. Thus the woman can exercise and not care how she looks. These clubs are very popular among 50 and older women and the guy that founded they has made a fortune syndicating them.
Those on this thread who support defeating this as a payback to feminism are actually supporting feminism. They are taking the option away from women to exercise in a same gender gym just like the feminists took it freedom of association away from men. Therefore they are promoting the same feminists ideas. Perhaps posters should spend their time defending the all women's gyms and leading the way back to all male groups.