Hey, I'm a libertarian--REAL big on personal freedoms. I support gay marriage. I'll use whatever gender pronoun a person wants me to. But there are women and parents of girls who do not want people with p**ises in the women's room. I dare say, without having seen any actual statistics on it, that there are likely many more that meet that description than there are pre-op transgenders who want to use the women's room. We're a country of majority rules. There's going to be one side of this that is unhappy about it no matter which way you go. The needs of the many outweigh the needs of the few.
If you haven't done so, please check out the meme linked in my previous reply and the comments for it. It is my hope that you understand, I'm not trying to be an asshole. I have legitimate concerns for the safety of women and girls.