Rushton and Bogaert (1987) asserted:
“We averaged the ethnographic data on erect penis and found the means to approximate: Orientals, 4 to 5.5 in. in length and 1.25 in. in diameter; Caucasians, 5.5 to 6 in. in length and 1.5 in. in diameter; blacks, 6.25 to 8 in. in length and 2 in. in diameter.”
Let’s examine with new average self-reported data from Herbenick et al. (2014).
Given that Herbenick’s study is more recent and rigorous, Rushton and Bogaert’s average values inflate African penile dimensions (erect length and girth) by over 23% while deflating East Asian penile dimensions by over 14% (assuming Herbenick is accurate) .
Contra European stereotypes, Herbenick et al. found ‘Asian’ penile length comparable to European (diff. = 0.04cm) and ‘Hispanic’ (diff. = 0.01 cm) lengths. For this and other reasons, there seems to be a lack of race realist commentary on this study.
There has been the usual racist assertion  that Herbenick’s average U.S. penile length value of 5.6″ (14.15 cm) is due to East Asian oversampling. A similar claim was made for Wessells, Lue & McAninch (1996), another U.S. study. Given that ‘Asians’ are a U.S. minority and not a priority sample in peer-reviewed studies, claims as these are unsustainable.
The small African sample size (n = 38) may have been due to the study controls which minimized self-reported penile measurement inflation.
This race/history/evolution notes post looks into more of Rushton’s claims.
[1.] Granted Rushton is making a claim about ‘Orientals’ and the ‘Asian’ data from Herbenick may contain South Asians. Rushton does however, conveniently classify African Americans (Afro-Europeans) as ‘black’.
[2.] For example, a commenter claimed: ” …. I bet asians drag down the average overall. Take asians out of the equation and I bet the average is 7 inches.”
Herbenick, D., Reece, M., Schick, V., and S. Sanders. 2014. Erect Penile Length and Circumference Dimensions of 1,661 Sexually Active Men in the United States. The Journal of Sexual Medicine 11(1): 93–101.
Rushton, J., and A. Bogaert. 1987. Race differences in sexual behavior: Testing an evolutionary hypothesis. Journal of Research in Personality 21(4): 529-551.
Wessells, H. Lue T., and J. McAninch. 1996. Penile length in the flaccid and erect states: guidelines for penile augmentation. The Journal of Urology 156(3): 995-997.