Subject: Will future Mars's colonists adapt to the new gravitational environment?

Hello,
I know that the long-term physiological effects of the lunar or martian 
gravitational environment are not currently known and that experiments 
aboard the International Space Station are planned, but I would like to know 
if you think that the first generation of humans (or animals, generally 
speaking) being born and raised in a lower-than-on-Earth gravitational field 
will consist in healthy individuals, perfectly adapted to their new 
environment (i.e. tall and slender-framed, but nevertheless healthy), or 
will they consist in abnormal individuals suffering from a collection of 
chronic bone and muscles diseases? In other words, will a new human 
subspecies appear spontaneously by a quasi-lamarckian process or there will 
be a slow darwinian evolution with many generations of abnormal and 
maladjusted individuals until their genes forget definitively their 
terrestrial origin and shape adapted beings to the new gravitational 
environment?
Thank you in advance,
Romain

Re: Will future Mars's colonists adapt to the new gravitational environment?