In the days of stupid kids getting pregnant and abortion being illegal, it made sense to enforce shared economic responsibility for the offspring of a careless act.
In the time of Abortion Rights and the Woman's Choice, it makes no sense. As the woman has 100% control over the decision to abort or give life, it must be her unshared responsibility to raise and provide for HER offspring. No, I don't really mean THAT! I mean the Law can no longer demand that the biological father provide economic support when he has no (legal) part in the decision to have the child.