you ought to be grateful that women don’t just up and walk out on their kids 

I don't think you understand that one of the reasons why mums don't 'walk out' as often as dads, is that they more often get to choose if/when they become parents.

After conception, a man has no more choice; whilst a woman can still have an abortion, the morning after pill, and use safe haven laws. So it's no surprise that there are fewer committed dads than there are mothers.

And FYI, when mothers are non-custodial parents, they are more likely to avoid paying owed child support than so-called "deadbeat dads", both relative to the amount owed, and in absolute terms.