Shouen-ai is pretty much yaoi right? It's not weird. To each his own. For me I like the tough-serious-swordsman/athlete-kind of girl, can't think their official japanese name, but those paired with the hero, who also has a sense of justice/unshakeable will. For two guys... I often find my pairings more for comedic relief, for girl to girl, I can't honestly take it seriously. More for the fact I'm no lady and don't understand the female brain. I have noticed though... from my experiences, role playing fanfiction shipping seem to be more popular in same-sex circles. Which makes me feel like an outsider sometimes :b.
I think at the core, it relies on a submissive person and a dominant person, regardless of gender. Two domineering or two submissive just don't click with me.