It is hard to pinpoint the references for his claims, since his article references the following blog post with a broken link:
From this blog post:
Testosterone levels are higher in black boys than in white boys as
early as 5 to 9 years of age (Abdelrahaman et al., 2005).
Oddly, the abstract of this article states that:
Total testosterone, the free androgen index, and
dehydroepiandrosterone increased with age in both groups, but after
adjusting for age, no racial differences were found.
Rohrmann et al. (2009) looked into the testosterone levels of neonates and found:
Androstanediol glucuronide, estradiol, and SHBG concentrations did not
differ by race; however, the molar ratio of testosterone to SHBG was
higher in African-American than white male babies after adjustment
(p=0.01). Both before and after adjustment, whites had higher
concentrations of IGF-1 (adjusted; white, African-American: 93.1, 71.9
ng/mL), IGF-2 (537.3, 474.8 ng/mL), and IGFBP-3 (1673, 1482 ng/mL)
than African-Americans (p<0.05), although the molar ratio of IGF-1
plus IGF-2 to IGFBP-3 did not differ by race.
So it seems that there may be some differences on average, at least at birth, although the verdict may still be out.
- Abdelrahaman, E., Raghavan, S., Baker, L., Weinrich, M., and Winters, S.J. (2005). Racial difference in circulating sex hormone-binding globulin levels in prepubertal boys. Metabolism, 54, 91-96.
- Rohrmann, Sabine, et al. "Racial variation in sex steroid hormones and the insulin-like growth factor axis in umbilical cord blood of male neonates." Cancer Epidemiology Biomarkers & Prevention 18.5 (2009): 1484-1491.