Digit ratio in men may correlate with genetic variation in the androgen receptor gene. Men with genes that produce androgen receptors that are less sensitive to testosterone (because they have more CAG repeats) have greater, i.e. more feminine, digit ratios. There are reports of a failure to replicate this finding. However, men carrying an androgen receptor with more CAG repeats compensate for the less sensitive receptor by secreting more testosterone, probably as a result of reduced negative feedback on gonadotropins. Thus, it is not clear that 2D:4D would be expected to correlate with CAG repeats, even if it accurately reflects prenatal androgen.