It's genetics, nutrition and doing things that optimise growth hormone that effect it. Taller parents will have taller kids generally. Countries that eat alot of dairy like Netherlands, Montenegro, Minnesota in US - tend to be taller. Countries like China increased height by 2-3 inches in school districts with mandatory milk programmes. milk increases Insulin like Growth Factor and has a very slow digesting protein (casein).

In the Netherlands they found that immigrants from Moroco and China had children that grew to the average height of the country probably by eating more similary to the Dutch.

During excercise and sleep growth hormone is released, it is reccomended that teens get 9 hours.