Do it in a vagina, or do it in a cup, I have no moral obligation to pay for your kid, and I believe that I have no legal obligation as well, from the blog of Ann Althouse:

When a man agrees to be his ex-girlfriend’s sperm donor…

… with a physician as intermediary and thereby avoids the obligation of paying child support, should he succeed if, later, he asks a court to require the mother to share custody of the child?

Turkey baster or no turkey baster, it is still your kid.