4. Becoming Martians
The people that settle on Mars probably won't come back to Earth and, inevitably, some of them are probably going to get busy. Presuming that exposure to cosmic radiation hasn't immediately sterilised them all, we could well be dealing with Martian babies. A large enough population would allow them to avoid inbreeding and perhaps produce the first ever, proper Martians. At this point, the population stop being migrants and become natives. Anthropologist Cameron Smith believes that this is how we secure our long term future in space. Not just by exploring and pushing back that final frontier, but by settling down, having families and attending the school sports day. An implication of this is, with Mars' weaker gravity, about a third of Earth's, the Martian babies might actually end up looking more alien than you'd think. It is thought that children raised on Mars would grow much taller than those on Earth. Obviously, the genes they inherit from their parents wouldn't change, but the reduced pressure on the spine would probably give them a good couple of extra inches in height. However, they would be much weaker than their Earth counterparts and even their parents (unless a special training programme was put in place) due to the fact that they are only fighting a third of the gravity to stay upright. This would mean that they would be unable to visit Earth, even if the technology made it possible, as it could cause them all kinds of muscular, skeletal and balance problems.