http://www.ncbi.nlm.nih.gov/pubmed/3455741
T'as raison vraisemblablement.
"Mean testosterone levels in blacks were 19% higher than in whites, and free testosterone levels were 21% higher. Both these differences were statistically significant. Adjustment by analysis of covariance for time of sampling, age, weight, alcohol use, cigarette smoking, and use of prescription drugs somewhat reduced the differences. After these adjustments were made, blacks had a 15% higher testosterone level and a 13% higher free testosterone level."
Une différence de 15% c'est quand même pas rien :p