But in the interest of furthering discussion.. I will say that nothing happened in my past to make me fear or hate men, and I've dated a few of them.
Sorry about your family member suffering abuse. It's very common for girls to be abused, much more common than statistics show, I think. Most of my friends have stories of sexual abuse (some are lesbians, but the majority of my friends are heterosexual).
I think the key to determining whether someone would have been a lesbian either way seems to be.. are they lesbians because they dislike men, or are they lesbians because they love women? You can get a feel for which they are when they speak about their relationships.
Hope that helps...