Katherine Gammon, writing for the website ""Life's Little Mysteries,"" speculates that children born on other planets are going to be taller than Earth children, mainly due to the lower gravity on world like Mars.

While research has been extensively conducted on the effects of micro gravity on humans, primarily on the International Space Station and the Soviet built Mir space station, the long term effects of low gravity are not well understood. The only experiences humans have in low gravity are three day sojourns in the one sixth gravity of the Moon during the Apollo lunar missions.
Further research waits for the day, presumed now to be distant, when people are working and living on the Moon and Mars. Clearly a child born and raised on the Moon or Mars is going to have problems if he or she were to venture to Earth, even considering that humans have evolved to deal with the Earth's gravity over millions of years. The muscles of such children will have atrophied compared to those born and raised on the green hills of Earth. Their bones are likely to be more brittle.
Just as researchers are trying to find ways to condition people against the long term effects of micro gravity, this prospect suggest that a useful line of research for a Lunar base or a Mars outpost would be to develop techniques that will condition people against the long term effects of low gravity.
Will exercise be useful? Without a doubt, but the time required to keep one in shape for a trip to Earth might not be worth it. Could a person who has lived their entire life on the Moon or Mars undergo a period of exercise that would bring them up to living under Earth gravity?
What about medication? Could drugs be used to strengthen bones and muscles to allow a person who has spent their entire lives on the Moon or Mars to visit Earth?
Maybe a combination of drugs and exercise would do the trick. But that is just speculation and needs to be studied with research. Otherwise, people who propose to immigrate to the Moon or Mars as settlers will be presented with a disquieting choice. They may be condemning their children, should they decide to have any, to living on those worlds pretty much forever. That might not be a bad prospect. Living life as a pioneer on a frontier world would likely be very fulfilling for most.
But just as many people on Earth look up at the night sky, wondering what life would be like in the freedom of space, would people on Mars, say, chafe at being made prisoners of gravity? One suspects that human ingenuity will take a hand and the children of Mars and of the Moon will yet be able to visit the Mother World of their ancestors and appreciate anew the cradle of a human civilization that is by their time expanding toward the stars.
(Source: Contributor Network)