Agarwal: But the skeleton is completely active. It's constantly turning itself over and rebuilding itself. And your entire skeleton in a sense remodels itself in 10 years, so in 10 years you have a whole new skeleton and how it remodels, what triggers it to remodel is something that's really just starting to be fully understood in bone biology.
Narrator: How remodeling happens differently between males and females is also not very well understood.
Agarwal: We've typically have thought, oh well, both of these things are related to activity and biomechanics in the skeleton but that women have this exception because they have this hormonal environment, but now one fully understands the differences. Males don't have the reproductive hormones that are influencing the skeleton, but they have other types of hormones. They've got androgens, which are equally important in the formation of the male skeleton.
Narrator: For Science Today, I'm Larissa Branin.