This thread is a tl;dr for me. I read the first page though.
First of all, wear your own freaking condom if you're doing one night stands. Second, if you're dating/otherwise know each other, there's this thing that adult people do.. You know, talk?
Okay, if you have had this diabolical woman who says she's on the pill if she's not, breaks your condoms or what ever, I think that it would be rational to not have to pay alimony (not sure about different laws on alimony) if you DON'T want to have the baby in the first place, and was tricked into it.
otherwise? Just freaking talk about it. Get another man if you REALLY, REALLY, REALLY, REALLY, REALLY want to have a baby, but your man doesn't.
If you're a man and REALLY, REALLY, REALLY, REALLY, REALLY don't want to have a baby, and she wants and won't stop nagging about it (nagging is not talking, women), get another woman.