Nobody knows. Human body too complex to simulate. No experiments with low gravity in space. Women in child with fetuses are not permitted on the ISS because we don't know enough about effect of zero g.

Lots of things change in the body in zero g, and the body is a balance of many systems, it could be worse in low g, or it could be that low g is better than full g, you can't just draw a straight line between zero g effects and full g to guess the effects of low g.

Also applies to growing children, they may not grow to maturity normally. There's no particular reason why humans born on Mars would grow up able to live on Mars as after all our bodies never evolved in low g - so why would they naturally adapt to work in low g either? It would have to be through mechanisms evolved for other reasons than to make a body work okay in low g - if so - why should they work together nicely to create a healthy growing body in low g? Might do, might not.

Also if it turns out to be impossible, it might be that this can be solved by living in centrifuge spinning habitats. That depends on matters such as human spin tolerance in conditions we can't simulate exactly on Earth.

But this is just one of many issues with the idea of living on Mars which is an extremely inhospitable planet with no atmosphere to speak of, no oxygen, and you'd need pressure suits to stay alive on the surface as like the vacuum of space, the moisture lining your lungs would boil. If you could live there comfortably, it would be dead easy to live full time 24/7 on the summit of Mount Everest. Our technology isn't there yet. But there are other issues also for planetary protection - all our exploration of Mars so far has been based around search for life there, it would be a huge anticlimax to find life and realize it is life we brought there ourselves

Great interest to explore though. See also Robert Walker's answer to How soon can humans move to and live on Mars?