One of my best friends, for the last 34 years or so, is a straight woman. We are still very close. It isn't an exclusive thing, but she tends to prefer the company of gay men, over straights of either gender or lesbians. She told me it's just because she seems to have more in common. But she is the type to have LOTS of friends, anyway. We have lots of friends in common, of both genders and all orientations. When I go back to visit, she usually throws a party for me, and invites "about 40 of our closest friends."