Why are some men hairier than others?

The variation in hairiness among men is primarily influenced by genetics, hormonal levels, and ethnicity. Testosterone and its derivatives play a significant role in hair growth, with higher levels often leading to thicker and denser body hair. Additionally, genetic predispositions can determine the density, distribution, and growth patterns of body hair. Ethnic background also contributes, as certain populations may have evolved with differing traits related to body hair.