well, I seem to recall that it's pretty much the woman's choice (not sure, don't quote me), but honestly, if she wants to abort the man's child and doesn't even want to talk about the issue, would you really still wanna be with that woman? I mean, even if you convinced her to keep it, I'd have some doubts about that relationship working
as for "Oops, I knocked her up and I wanna keep the baby"...well, if she aborts, she's a snarling female dog IMHO, but what can you expect from a one night stand?