[Starbuck]

(This is Gaius, I forgot I was on my mule!)

I'm sure they'd the right to live wherever they want once they are adults. But Coda brings up a couple of good points - it would probably be more difficult to move to Earth from Mars than to move between most places on Earth. I do see the ethical concern you're bringing up, but I also see Coda's other point, which is that no matter where or how you're brought up as a child, you will always get different opportunities than other children, sometimes more opportunities and sometimes less, but that difference is always there even if we take Mars out of the picture. So I still don't know if raising a child on Mars is any worse than raising a child anywhere on Earth.

Also, while I can't speak for other countries, I highly doubt the U.S. would prevent any adult living in an American Mars colony from returning to Earth if a return trip was feasible. Though it might take a while to arrange, depending on how often trips between the two planets are being made at the time.