Assessing Rushton and Bogaert (1987)

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) [1].

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 [2] 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.


Ethnic Androgen Differentials I

Testosterone Molecule

Masculinizing: Total Testosterone (T), Circulating Free Testosterone (cFT)

Feminizing: Estrone (E1) & Estradiol (E2)

The race realist assertion that (East) Asians have less testosterone (T) than Europeans who have less than Africans is mistaken on multiple levels. Here is Rushton (2000b):

The races differ in their level of sex hormones. Hormone levels are highest in Blacks and the lowest in Orientals. This may tell us why Black women have premenstrual syndrome (PMS) the most and Orientals the least. The races also differ in testosterone level which helps to explain men’s behavior. In one study of college students, testosterone levels were 10 to 20% higher in Blacks than in Whites. For an older sample of U.S. military veterans, Blacks had levels 3% higher than Whites (see the 1992 issue of Steroids). In a study of university students, Black Americans had 10 to 15% higher levels than White Americans. The Japanese (in Japan) had even lower levels.

Rushton (2000a) states it thus:

One study of matched groups of 50 black and 50 white male college students in California found that testosterone levels were 19 percent higher in blacks than in whites (Ross, Bernstein, Judd, Hanisch, Pike, & Henderson, 1986). A 3 percent difference favoring blacks has been found among an older group of 3, 654 white and 525 black male Vietnam era military veterans (Ellis & Nyborg, 1992)…… Measurements of two metabolites if dihydrostesterone shows marked lower levels in the serum of Japanese natives and 10 to 15 percent higher concentrations in American blacks (Hixson, 1992).

Here Rushton (2000a, 2000b) uses three studies; the first is Ross et al. (1986) which found that aged matched African American (AA) college students had 19% more testosterone than European American (EA) college students. His first study thus has the following problems:

  • African Americans are a mixed sub-clade (with European, American, East Asian) of the African clade and most likely does not represent unmixed Africans;
  • European Americans are a sub-clade of the European clade and might not necessarily represent unmixed Europeans as some 20-30% have African ancestry [Stuckert (1958)] with additional others having American and East Asian ancestry;
  • Small sample size (n = 100, 50 AA); and
  • Sample bias: university students do not represent the average population. This is a bias typical of peer-reviewed studies.

Granted the study’s authors make the same mistakes and even more. Blood samples were collected at times convenient to the students between 10 A.M. and 3 P.M. Timing affects testosterone levels. While the students were age matched, they were not weight matched.

ead1From their table 1 data above, the African Americans (AA) were over 11 lbs heavier than the European Americans (EA). And yes, weight can affect T-levels if the additional weight indicates adiposity. The study authors adjusted for weight:

Adjustment by analysis of covariance for time of sampling, age, weight, alcohol use, cigarette smoking, and use of prescription drugs somewhat reduced the differences. After these adjustments were made, blacks had a 15% higher testosterone level and a 13% higher free testosterone level.

So Rushton (a double doctorate psychologist who knows about variable adjustments) did not read properly.

ead2Note as well that table 2 indicates more feminizing E1 and E2 for AA males. Notice also that AAs have 18.6% more total-T and 21.1% more free-T (cFT) than EAs. Thus Rushton is referring to the total-T values when he uses 19% which is yet another problem. He should be more concerned with the cFT values.

The second study Rushton (2000a, 2000b) uses is Ellis & Nyborg (1992) which examines 4462 army veterans of African American and European American descent. Army veterans may be more predisposed to aggressiveness and higher testosterone levels thus presenting a possible bias.

From the abstract:

Racial and ethnic variations in serum testosterone levels were investigated among a large sample of male Vietnam era veterans. Based on geometric means, significant average differences were found between 3,654 non-Hispanic white and 525 black individuals. The geometric mean for testosterone levels among 200 Hispanic individuals was similar to that of non-Hispanic white individuals. Regarding two other racial/ethnic groups (Asian/Pacific Islanders and Native Americans), no significant differences were found, due perhaps to small sample sizes. Results were interpreted as having considerable potential for explaining some of the race differences in the incidences of cardiovascular diseases, hypertension, and prostate cancer.

Given Rushton’s thesis, this study presents nothing in his defense. A 3% difference is insignificant and can be simple fluctuations due to any number or combination of conditions. Why the study would call this “significant average differences” is unknown. Given no significant differences found in East Asian sub-clades (Hispanics, Asian/Pacific Islanders, Native Americans), this study hurts his cause. Unfortunately I do not have access to this study to probe further.

The third study is Hixson (1992) which is actually not a study but a medical report. In Rushton (2000a), the reference is stated as:

Hixson, J. R. (1992, October 20). Benign prostatic hypertrophy drug to be tested in prostate CA prevention. The Medical Post.

Even if Hixson (1992) was a study, the Japanese can never be indicative of all East Asians. Thus we can conclude that Rushton’s thesis in unstable and unscientific.

Problems with ethnic androgen differential studies is summed up by Kehinde et al. (2006) which states:

However, several studies have sought racial–ethnic differences in circulating androgen levels with conflicting results [2, 13, 14]. Thus, while Ross et al. [2] found a statistically significant higher TT (19%) and free testosterone (21%) levels in young African-American men compared to Caucasians, Wright et al. [13], Ellis and Nyberg [14] found higher but statistically insignificant testosterone, free testosterone and SHBG levels in comparable groups of African-American men and Caucasians living in various parts of the USA. These studies may however been flawed by small sample size, for example, Ross et al. [2] studied only 50 young men (20–30 years old) from each racial group and Wright et al. [13] studied a total of 33 men in both racial groups who were 20–40 years old. Other flaws of some of the earlier studies include inappropriate sample collection and storage, for example while Ellis and Nyborg [14] studied 525 African-American and 3654 Caucasian men, unfortunately the blood samples were collected at various times during the day in this study. It is now well established that diurnal variation exists in circulating testosterone concentrations in men with the highest levels found at 8.00 am and lowest levels at 8.00 pm [15, 16]. All of these flaws may be responsible for the conflicts in the association between steroid and steroid metabolites levels and aetiology of prostate cancer.

It had been suggested that, prolonged exposure (i.e. from <30 years of age) to high androgen levels in African-American and Caucasians compared to the Chinese is the basis for the observed difference in the effect of androgens in various racial/ethnic groups although other environmental, metabolic, dietary and genetic factors may also have important contributory factors [17].

The sources used in Kehinde et al. (2006) are:

2. Ross RK, Bernstein L, Judd H et al. Serum testosterone levels in healthy young black and white men. JCNI 1986; 76: 45–48.
13. Wright NM, Renault J, Willi S et al. Greater secretion of growth hormone in black than in white men: possible factor in greater bone mineral density. A clinical research study. J Clin Endocrinol Metab 1995; 80: 2291–2292.
14. Ellis L, Nyberg H. Racial/ethnic variation in male testosterone levels; a probable contributor to group differences in health. Steroids 1992; 57: 72–75.
15. Winters SJ, Brufsky A, Weissfeld J et al. Testosterone, sex hormone binding globulin and body composition in young adult African American and Caucasian men. Metabolism 2001; 50: 1242–1247.
16. Veldhius JD, King J, Urban RJ et al. Operating characteristics of the male hypothalamo-pituitary-gonadal axis: pulsatile release of testosterone and FSH and their temporal coupling with lutenising hormone. J Clin Encocrinol Metab 1987; 65: 929–941.
17. Santner SJ, Albertson B, Zhang GY et al. Comparative rates of androgen production and metabolism in Caucasian and Chinese subjects. J Clin Endocrinol Metab 1998; 83: 2104–2109.

NOTE: Helmuth Nyborg is a Danish race realist psychologist.


L. Ellis., and H. Nyborg. 1992. Racial/ethnic variations in male testosterone levels: a probable contributor to group differences in health. Steroids 57(2): 72-75.

Ross, R., Bernstein, L., Judd, H., et al. 1986. Serum Testosterone Levels in Healthy Young Black and White Men. Journal of the National Cancer Institute 76(1): 45-48.

Rushton, J. 2000a. Race, Evolution, and Behavior: A Life History Perspective. Port Huron, USA: Charles Darwin Research Institute.

Rushton, J. 2000b. Race, Evolution, and Behavior: A Life History Perspective. 2nd special abridged edition. Port Huron, USA: Charles Darwin Research Institute.

Stuckert, Robert. 1958. African Ancestry of the White American Population. The Ohio Journal of Science 58(3): 155-160.

Condoms and Ethnicity II

[This is a continuation of Condoms & Ethnicity I]

UPDATE: 2013-10-27: A latter portion of the post has been invalidated, my apologies.

UPDATE: 2013-08-31: The claim at this link is incorrect. The WHO report was written by an Australian condom manufacturer who arbitrarily used these three studies to propose that different sizes may be preferred by persons in different countries. These studies do NOT indicate that penile width differs by ethnic group as none of the studies were performed by medical professionals nor were they replicated.

The Family Health International (FHI) & JP Rushton

In a FHI monograph by Spruyt (1996), we read:

The World Health Organization bases its specifications for condom width on consumer preference and penis size, citing three studies. Taken together, the studies show significant variations in penis size within all population groups, but also indicate that men of African descent on average have a slightly wider and longer penis size, Caucasian men have a medium size, and Asian men a slightly narrower and shorter size (WHO).

Based on the consideration that anatomical differences exist among regions, a series of FHI studies were conducted in three Asian countries to compare small and standard width condoms (49 mm and 52 mm), and in three African countries to compare larger and standard width condoms (55 mm and 52 mm). Among the African sites, breakage rates were slightly higher and slippage was slightly lower for the smaller of the two condoms being compared. (Joanis) However, results from the Asian sites were inconsistent. (Neupane; Andrada) Moreover, almost none of the differences in breakage and slippage rates from either the Asian or African sites were statistically significant. Thus, results from these studies pertaining to penis size and condom failure were inconclusive.

So the FHI found it necessary to launch three studies based on one page of a WHO condom report. The report itself (WHO 1998) is most interesting and highlights the need for not accepting data at face value.


The table below is the one page WHO listing of three studies which purport to show ethnic variations in both penile length and girth.

Unsurprisingly, infamous race realist Rushton (2000) poses questions and answers using the same WHO data in his book Race, Evolution, and Behavior: A Life History Perspective. Two questions are of importance to penis variations and source analysis.

Q: Doesn’t the evidence on race and penis size come from 19th Century stories by racist Europeans in colonial Africa?

A: The earliest findings come from the Arabic explorers in Africa and one study by a French army surgeon originally published in 1898. More up-to-date information comes from the World Health Organization. Their studies show the same three-way race pattern as do all the other studies.

Q: Isn’t the material on race and sex a kind of pornography? Isn’t race controversial enough without bringing sex and AIDS into the picture?

A: One World Health Organization study I mentioned in the previous answer examined penis size in order to provide the right size condoms to slow the spread of AIDS. Finding out which groups are most at risk for sexually transmitted diseases can help slow their spread and save lives.

ANALYSIS: The WHO did not study penis sizes. It relied on three separate studies, two of which were not peer-reviewed and the data was included as “Appendix III” (which should have alerted Rushton that this was not an original study). The first study references Africans in the US (not Africa!) and Europeans in the US (not Europe!), the second Europeans in Australia (not Europe!) and the third, Thais.

The first study is Alfred Kinsey’s flawed self-reported study on incarcerated males (a highly truthful bunch no doubt). The sampling, methodology and measurements are biased.

The reference for Asians is stated as an unpublished study by Bangkok Medical University (Muangman 1978) and nothing is known about the sample size or methodology (besides that prostitutes measured with paper tapes). Thus this is another biased study and does not represent the average Thai male.

The Aussie study was peer-reviewed but submitted a method for self-measurement. For a sample of 156, they found an average erect length of 15.99 cm or 6.3” (Richters, Gerofi & Donovan 1995 as mentioned in Mondaini et al. 2002) which is larger than Rushton’s upper European limit of 6″. While this value of 15.99 cm is the largest value from 8 different studies (Promodu et al. 2007), it does seem accurate given another study.

Estimated applicability of Rushton’s values to the WHO data

Rushton proposes to have found the following: East Asians: 4 to 5.5″ (10.2 to 14.0 cm) in length and 1.25″ (3.2 cm) in diameter, Europeans: 5.5 to 6″ (14 to 5.2 cm) in length and 1.5″ (3.8 cm) in diameter and Africans: 6.25 to 8″  (15.9 to 20.3 cm) in length and 2″ (5.1 cm) in diameter. In other words, the average European is 21% longer and 50% thicker than the average East Asian, while an average African is 50% longer and 60% thicker.

Kinsey - US EuropeansIf this link is accurate (see pic above), Rushton’s US European length claim only correlates some 43% with that of Kinsey’s data. The Thai study found 51% with 5 to 5.9” penises which correlates more than that for Europeans and yet is larger than his 4 to 5.5″ assertion.

The WHO girth data gives 29% of Euro-Americans, 68% of Euro-Australians, 34% of Afro-Americans and 17% of Thais having circumferences above 5”. Why so large a value for Aussie-Europeans compared to US Europeans? A portion of the WHO states:

Condoms are made in various widths. Based on studies in Australia, Thailand and the USA, and the experience of major agencies, the wider condoms (flat width 52-55 mm) will be preferred in Australia, Africa, Europe, Latin America, the Middle East and North America, and the narrower condoms (47-51 mm) will be preferred in several Asian countries (see Appendix III). Other widths are also made for small specialized markets.

[This portion has been invalidated, see comments below] While wondering which Asian countries are being referenced and if any are not, one would be inclined to treat the ‘experience of major [unnamed] agencies’ as authoritative. The Asian preferred circumference range is 147.7 to 160.2 mm. Similarly, the non-Asian preference circumference is 163.4 to 172.8 mm. From the data, 95% of Euro-Americans, 91% of Afro-Americans, 86% of Euro-Australians and 100% of Thais have penile girths less than or equal to 150 mm. Why then would there be a preference among Africans and Europeans for condoms some 13.4 to 32.8 mm larger?

2013-02-22, update: The answer to the last question can be found here, here and here.


Andrada A, Ravelo N, Spruyt A, et al. 1993. Acceptability and Functionality of Standard and Smaller Latex Condoms during Human Use: Philippines. Durham, USA: Family Health International.

Joanis, C., Brookshire, T., Piedrahita, C., Steiner, M., Diakite, M., and J. Esibi. 1990. Evaluation of Two Condom Designs: A Comparison of Standard and Larger Condoms in Ghana, Kenya, and Mali. Durham, USA: Family Health International.

Mondaini, N., Ponchietti, R., Gontero, P., et al. 2002. Penile length is normal in most men seeking penile lengthening procedures. International Journal of Impotence Research 14: 283-286.

Muangman, D. 1978. Report on measurement of Thai male genital sizes and recommendation for appropriate condom usage [unpublished paper]. Bangkok Faculty of Public Health, Mahidol University.

Neupane, S., Abeywickrema, D., Martinez, K., et al. 1992. Acceptability and Actual Use Breakage and Slippage Rates of Standard and Smaller Latex Condoms: Nepal and Sri Lanka. Durham, USA: Family Health International.

Promodu, K., Shanmughadas, K., Bhat, S., and K. Nair. 2007. Penile length and circumference: an Indian study. International Journal of Impotence Research 19: 558-563.

Richters J., Gerofi J., and B. Donovan. 1995. Are condoms the right size(s): a method for self measurements of erect penis. Venerology 8: 77-81.

Rushton, J.P. 2000. Race, Evolution, and Behavior: A Life History Perspective. Port Huron, USA: Charles Darwin Research Institute.

Spruyt, Alan. 1996. User Behavior and Characteristics related to Condom Failure in McNeill, E., et al. (eds.) The Latex Condom: Recent Advances, Future Directions. Durham, USA: Family Health International. [accessed: 2012-01-15].

WHO. 1998. The Male Latex Condom: Specification & Guidelines for Condom Procurement. WHO & Joint UN Programme on HIV/AIDS. [accessed: 2012-01-23].