Postnatal penile length and growth rate correlate to serum testosterone levels: a longitudinal study of 1962 normal boys

Abstract

We found that endogenous testosterone was significantly associated with penile size and growth rate in infant boys. Thus, the postnatal surge in reproductive hormones appears to be important for genital growth. Our data may serve as an updated reference for normal penile length in Caucasian boys up to 3 years of age.