If they're already born then obviously there's nothing to do. However, what I'm talking about is the same as the abortion debate, about allowing a parent to choose whether they want to rear a child or not.

The difference is not in the act, but the information the decision is based on.

Choosing not to have a child because of you are unable to safely raise it, is one thing. (can't afford to raise a child; mother is too young; rape victims)

Choosing not to have a child because it's genetic code doesn't fit your notion of good. Is another. (Downs; autism; gender; eye color)

Children with Down syndrome, severe autism, and other disabilities are significantly harder to raise than children without, often requiring lifelong care. This falls under your first criterion (“choosing not to have a child because ~of~ you are unable to safely raise it”). Gender and eye color do not fall under this criterion.

(Tangentially, this is a question that supporters of unconditional access to abortion do not have a good answer for. If abortion is 100% legal, without exception, does that mean it’s OK to use it for female infanticide?)

Same for the autistic and mentally ill. I'd like to just roll the dice until I get one that'll be easy to raise. And in much of the world girls are indeed much harder to raise