They include Markus Nöthen, a genomics professor at Germany's University of Bonn. Nöthen and colleagues say they've found a gene variation that may explain some cases of male pattern baldness (androgenetic alopecia), the most common form of hair loss, which is related to the male sex hormones.
The suspect gene variation sits on the X chromosome, which is handed down to men by their mother. So a man may get an idea of his scalp's future from men on his mother's side of the family.
While hereditary factors are an important cause of hair loss, other factors also influence hair growth and loss.
A white man's chance of male pattern baldness increases with age; in his 50s, he has a 50 percent chance of having at least some hair loss, the study shows.
Clues From Granddad
"The fact that family studies of [male pattern baldness] have typically stressed the resemblance of fathers and sons is understandable, given the differences in patterns of hair loss between males and females," write Nöthen and colleagues.
"Our genetic data, however, stress the relative importance of the maternal line in the inheritance of [male pattern baldness]. This suggests that ... the resemblance should be greater between affected males and their maternal grandfathers than between affected males and their fathers."