It's not the nine months of gestation that's the barrier, it's the subsequent 25 years of child rearing. And as a society we value individuals and not just quantities: if I'm accused of infanticide offering to have another child will not balance the criminal books.
What happens when AI is a more effective parent/teacher than humans?
It's never away or preoccupied with work, never loses its temper or fights with the other parent, never too tired to play or engage with questions, the list goes on.
I'm not even suggesting heated robotic caregivers. Humans could still be employed to carry out its instructions in the real world, from hugs to diapers.
As dystopian as it sounds to us today, it's possible that such a system could consistently raise more well-adjusted adults while also being cheaper and freeing most adults from the burdens (as well as most joys) of parenthood.
In the future, AI may be so much better than humans that raising a child by hand is borderline illegal, except for a few religiously exempt groups.
