I agree with Ericschand. People just dont seem to accept the responsibility that comes with having sex in the first place. Everyone with an elementary level education knows how babies are made, and its a risk you take every time you have sex, irregardless of contraception (even Vasectomies are not considered totally 100%). By engaging in intercourse with someone, you are automatically accepting this responsibility whether you like it or not. It takes 2 to get someone pregnant, so that conniving girlfriend of yours couldnt have done it without your conscious decision. You gave her the sperm, so deal with it!
That said, she is the one physically going through pregnancy, and there's not much you can do to stop it without harming her body, so ultimately the decision has to be with her. Tough luck, but you knew and accepted the risks, so pay the damn child support.
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Lovely Wendie99