Combat Global warming/climate change, control population, save on welfare and lead to a more educated and prosperous society. One Child Policy helps cure a few problems that plague other developing nations. 

I think it's a great policy. People here in America having 20 kids so they can get more money from welfare.

There isn't quite as much a correspondence to women's lib and birthrates anyway. For its levels of economic development, Japan is severely backwards when it comes to women's rights (I think abortion is still outright illegal there, culture looks the other way on rape and sexual harrassment which are nominally illegal, similarly with prostitution), but has perhaps the lowest birth rate on the planet

Examples like that would point to the mere fact of economic development itself, with the only outlier being America

No, I'd say it would be more possible to live Armored Core 4 Answers style in flying ships sustained by massive energy generators on the Earth. But I would definitely say that would be impractical for human advancement.

Well... it probably didn't help that their women's rights movement was basically the Allied goverments telling Japan that they were now giving women the right to vote.

I can't really speak on Japan though.  Sometimes I hear stories where people say women's rights are horrible there, other times I hear people say it's a lie and women's rights are great over there....

and it's basically never anyone FROM Japan.

As for culture looking the other way on sexual harrasment and rape... i'll asume you mean moreso then average in anycase.

The issue of Prostitution is a hard one to quantify in the terms of gender rights though, unless your just talking about the general attitude shown towards prostitutes.

In practice the making it illegal to solicit prostitution but not being illegal to be a prostitute seems to get the best results... but it's a pretty illogical setup as far as things go on paper.

Though, so is prostiution being illegal, but porn filming being legal.  Paying for sex is illegal... but if I pay for sex and film it... now THAT is legal.

Not to get off track, but i imagine they could get around that through a licensing system similar to how Nintendo keeps the riffraff off their SDK's: you would need a license to film pornography, and need a registered company that operates on a properly zoned "set," probably similar to how the Netherlands has legalized prostitution, by making it a clearly delineated and regulated trade (or how you have to sell liquor in Pennsylvania)

Because that is a pretty egregious loophole. I mean, everyone has webcams at least now, and any sort of filming could just be called amateur porn, and the exchange of money the hiring of a performer.

And i think it would be safe to say that Japan is clearly worse in at least a few of those regards. Teachers molesting students is definitely a zero-tolerance thing here, but only on paper there...

Actually, no. Muslims are encouraged to engage in sex often (after marriage) not only for reproduction, but also for enjoyment (no ban on contraceptives).

Most people's ideas abour sex in Islam stem from the middle eastern countries which practice sex only when the intention is to conceive a child. This is a cultural phenomenon, not a religious one.

Or get their own reality show.

Out of curiosity does this apply to married couples, or can men only do this (including with women who are not their wives)?

And these practices usually are cultural, but religion and culture often interwine.

Octomom didn't want that, or at least she regrets it. She just wants to live normally, or so she claimed on her last interview on Oprah like a week ago