What are the reasons for men not to take responsibility when women get pregnant?

I too have wondered this. I mean, us women have not laid down with ourselves and gotten ourselves pregnant. I just think that men, just want to be boggled down with caring for a child maybe I'm not sure. I had a friend, who had gotten pregnant twice by the same guy and he too wanted nothing to do with the children and he would not care for them, until he knew for sure that they were his kids. Then after finding out, he went away into the military and now he is living in another state. He hardly sees his children and when he does its only for an hour or two. The only thing that he does is pay his child support. And that is not even enough in its own.

i told to my bf i was having a baby when i was one month pregnant, he stop talking to me... i think he was upset... i do not mind he doesn`t want to be with me, but what really hurts me is to see he doesn`t want to know anything about my baby... she is one year old and when she sees my brother, she called him "dad", she is a very sweet little girl... but i think he liked to be free, that`s the only reason i can think... i didn`t ask for anything, i just wantted him to keep in touch, but he even gave me fake e-mail address.... i really do not get him... but anyway he is the one loosing a great opportunity to see a beautifull litlle girl and he is not giving to himself the opportunity to recive a little bit of love from her.