I'm just not sure why having children is more important than other aspirations or, for that matter, why child-rearing ought to be specific to women.

Honestly, it's because I'm working under the assumption that childcare is necessary labor to sustain the population and thus maintain society. But if you believe that most jobs are going to be automated away in the future, and so less people would be a better thing, and childcare is a non-essential choice, I can see where you're coming from. Indeed, a basic income would be liberating for everyone, including women.

But I'm still confused by your lack of concern about the lack of leverage that women have relative to men and the real indignities that it enables. Again, back to the geopolitical analogy: Would you advise a country to not maintain a standing army just because taxes infringe a bit on free choice? How, then, will the country defend itself from the threat of external aggression or secure its state interests against its competitors? Why is it any different when it comes to competition between classes?

One last thing, we do have some maternity leave in the US, but it's atrocious compared to what exists in almost every other country.