My opinion is it's another reason women only want equality when it suits them. If it was mandatory to put a mans name on a birth certificate (after all men should have equal rights to their children, no?) then it should also be mandatory to have it confirmed by a DNA test and hold them accountable for their bastards. But then less women will be able to cheat successfully and trap men, so they will oppose it.
I would like it if all children were DNA checked and given a full genome map so when they were looking for a mate at some future date, they would have something to check and maybe avoid genetic problems in their children. It seems that might be more important than hiding the fact that a child might not be someones blood. I even suspect of that 15% many of the men would still agree to raise that child as there own in order to keep the woman they married.