If their mother has enough time to get laid, she should have the time and dedication to raise her child correctly too. That goes for the father too, of course. If you aren't gonna take care of what you give birth to, use protection to prevent the poor child from suffering.
hmmmmm What if the mother was raped?
Also, ask yourself this question: Whats more damaging to the human race; killing an unborn fetus, or bringing another child into this overpopulated, polluted, impoverished, self destructing cesspool people call a planet?