How does a person attains a medium height? What are the genotype of these genes?
or is it the role of growth hormone and other hormones.

In human beings, height is a quantitative or metric trait, that is a characteristic that is measured in quantity and controlled by multiple genes and environmental factors. It is estimated that about 60 to 80 percent of the difference in height between individuals is determined by genetic factors, whereas, 20 to 40 percent can be attributed to environmental effects i.e, nutrition.