The right to decide what happens inside a womans body is hers to decide and hers alone (as long as she complies with the laws in the US). So if she wants to have a legal abortion (again, in accordance to the US laws) than that is her choice and nobody else's decision.
And with sperm banks women don't actually need a man to get pregnant anyway.
If a man knocks up a woman he is the one who is running the risk of the girl having this baby and him having to pay for it. In hindsight he might have been a bit more smart and used protection.
And I do not give a crap about the number of kids that are born to mothers who do not know the identity of the person who made her pregnant, but just like this woman that woman too would have been totally within her legal and moral right not to have him present in the delivery room.
And again, I could care less if this guy thinks he is the father. Until the baby is actually born he is nothing, not a single thing in the eyes of the law.
And there is nothing wrong with that picture, there is possibly something wrong with the woman for having sex in a non-committed relation but there is most certainly something wrong with the guy, he was careless and impregnated a woman and that is almost entirely down to his own stupid decisions.
Sorry, I cannot feel guilty for some dumb schmuck who got a woman pregnant he did not want to get pregnant. He cannot claim he was not an active participant in that act so he has to pay the piper.