Environment major factor in growth.

If you volunteer to colonize the moon or Mars, you can expect your kids born there to look different and move quite differently than you do by the time they start kindergarten. Then, if you plan to send them to boarding school on Earth, you may need some extra cash for a wheelchair, golf cart, or caretaker to help them move about, maintains Dennis Carter, a Stanford University specialist in biomechanical engineering.

Current scientific explanations of how we become who we are may overestimate the role of the genome inside that single cell from which all humans begin. Carter contends that it will not take generations of genetic evolution in a changed environment to substantially change your descendants. He and his students have demonstrated that bones aren't told how to grow by the genome nearly so much as they are shaped by biomechanical construction rules, which are based on the environment inside the womb and on Earth. Just as there are rules for constructing bridges and buildings that will stand up to the physical forces in their environment, so there are rules for the construction of bones--and, most likely, other tissues--within an animal species.

Carter and his class have been able to write those rules, in the form of mathematical formulas...