If the mother doesn't care that the father walks away. If the mother does care and points out who the fater was, but the father disagrees then he has to (dis)prove it. DNA test should be pretty accurate.
well i thought you couldn't legally force anyone to surrender their DNA for testing. when there is a murder they go around asking suspects to voluntarily submit to dna testing.
so basically, if someone accuses you of fathering their baby, you either have to raise the kid or give up your dna? your valuable dna? because that would make a good movie. where they steal a guys dna.