Aktshually, I don't remember which state, but once there was a time, that they decided to give custody over 4< year olds to dad's automatically and immediately it caused 60% increase in child mortality. So the decision was withdrawn eventually.
So, if true, then it's simply because women are the ones who are in presence of babies and hovering them. Men just leave and forget about it's existence. When an infanticide happens, why do you chuds never ask, where was the father? Why did he not protect his spawn from mentally unstable mother? Why did he choose to procreate with crazy in the first place? Rightfully, leaving a recently birthed mother, abusing her or choosing to hide from home duties at 12h job should all be considered child abuse, because the one suffering from it the most is the child. But that will never be considered because we lib in a saciety that coddled men at every corner.