What's this manga of which you speak? BBC News discovers manga, notably yaoi, and cosplay parties:

"Yaoi is all about two men, in love, having sex, and a lot of girls are desperately wanting a love relationship. But those two men are not attracted because they are gay - that's the key point. They are attracted because they are in love with each other. I think a lot of women who read Yaoi Doujinshi, are interested in sex, but also they are rejecting their sexuality as well."