Space Age Magazine

So having grown up on Mars they might be unable to ever visit the Earth?

If that seemed likely, it might make potential colonists think twice about raising their kids on Mars or (even more so) the Moon.

True, as a martian child I'd probably want to visit my heritage. But I was reading somewhere, I can't quite remember where (I think it was a Space.com article), about how we may have to change ourselves to adapt to an environment. While we're probably a long way off of an Avatar-like situation, I don't think it's impossible to conceive growing a new body for yourself or your children with appropriate biochemistries suited for whatever world you attempting to colonise. Especially given recent breakthroughs and hopefully near future breakthroughs in synthetic biology (Google 'Craig Venter').

True, biotech, nanotechnology, and cybernetics will probably offset the disadvantages of non-terrestrial environments in the long term.

I have no idea, my only exercise is walking my dog to the park where I throw a frisbee for an hour