Exactly, you hand them over to the state, which a pregnant woman cannot do (yet)

So because nobody else can keep the child alive, the mother HAS to offer her body to keep them alive for 9 months? I personally disagree with that

Most adult body parts, such as kidneys, won't "fit" inside a child, but if it's a matter of say a blood/marrow donation, then I think parents should be required to do so, unless they've given their child over to the state. I don't think there'd be many parents who'd refuse to give blood if it'd save the life of their child

I respect that view, and I think it's consistent with your principles. But my issue is that's not the way our system works, and very few people advocate for it to be that way. Everyone seems fine to dump all the 'consequences of sex' on the mother to carry the child the term, and then once she gives birth, all of those consequences disappear and nobody has to risk their life or their health to keep the child alive. That's why I personally feel like anti-abortion laws diminish the bodily autonomy of women because nobody else is forced to suffer the consequences.