For me, the issue comes from 1) failing to notify him she is pregnant and 2) more importantly, lie to him if he asks if the baby is his.
My oldest son has not seen his father since he was 6 weeks old. His father made no bones about the fact he didn't want our son, thinks he should have been aborted or "offered up for adoption." He said he never wanted to see or hear about our son again. He has never paid child support (of course, I never filed for it as I don't need it) and that is the way it is. But he knows he exists. And he knows how to contact me.
Granted, I don't know how my son will turn out in the long run, but at 8 1/2 he is a star student and has a fabulous personality. So for me, I don't think every child has to have two parents involved to turn out to be a productive member of society (and since my sons father never wanted him and wants nothing to do with him, it is probably better he is not involved) but I do believe every parent should be given the opportunity to be involved, if they choose to do so, except in cases of rape. I think to lie to a man and say the child is from artificial insemination because you want the baby all to yourself is horrible, IMO. If you wanted the baby all to yourself, you should have used artificial insemination.