Studies show that blacks don't have markedly higher levels of testosterone than whites, but recent research suggests that they might be more sensitive to it.
A difference has been found in androgen receptors which vary in the their number of glutamines (an amino acid). The length of the glutamine chain is important in determining a person's sensitivity to testosterone. The shorter the chain, the more sensitive.
Black men have shorter glutamine chains than white men, and this difference might help explain the higher rate of prostate cancer among blacks.
Having short chains is also linked to ADHD, conduct disorder, and oppositional defiant disorder--disorders which are more prevalent among blacks (in symptoms, but not diagnosis).
These disorders strongly predict a lifecourse-persistent pattern of criminality, a pattern also seen more frequently in blacks compared to whites.