Are gay men bigger?

One study of the Kinsey data says gay men reported bigger cocks. What it measured, how, what critics said and why nobody has confirmed it since

Every few years a headline announces that gay men are bigger, and every few years it gets shared with the same mix of pride and suspicion. The claim is real in the sense that a published study found it. Whether it is true is another matter. Almost everything rests on one paper from 1999, built on data collected before most of its readers were born.

What the study found

The psychologists Anthony Bogaert and Scott Hershberger went back to the archive of the Kinsey Institute, where Alfred Kinsey's team had interviewed thousands of men between 1938 and 1963. They selected 5,122 men and split them into two groups, 935 homosexual and 4,187 heterosexual. Kinsey's protocol had recorded five measures: length and circumference soft, length and circumference erect, and the man's own estimate of his erect length. On all five, the homosexual men reported larger cocks than the heterosexual men.

The differences were small. The figure that all secondary reports agree on is erect circumference: 12.6 cm4.95 in for the gay men against 12.2 cm4.80 in for the straight men. For erect length, the summaries quote slightly different numbers, but they agree that the gay men were about a third of an inch longer, under a centimetre.

The authors suggested an explanation: the prenatal hormones that shape the genitals might also play a part in shaping sexual orientation, so the two could vary together. It is an interesting idea. It is also an idea, not a finding.

How it was measured

This is the weak point. Nobody in a white coat measured these men. Kinsey's team gave them cards and instructions, and the men measured themselves at home and sent the figures back, or reported them during the interview. Every number in the study is a self-measurement, taken in private, by a man who knew it was being recorded.

As the rest of this site shows, self-measured sizes run big. College men asked their size answer far above the clinic average, and the men who care most about looking good add the most (see Why everyone adds an inch). If one group was even slightly more motivated to round up, or slightly more aroused while measuring, the whole difference could come from that.

The criticisms

Within a year the study drew a published comment by W. Krisel in the same journal, and Bogaert replied. The broader objections, summarised by the sex researcher Justin Lehmiller, are easy to list:

• Self-reported data. The men measured themselves, with no check.
• Possible exaggeration. The two groups may have exaggerated by different amounts.
• Possible differences in arousal. A fuller erection while measuring would give a bigger number.
• A non-representative sample. Volunteers, not a random cross-section.
• Old data. Collected between 1938 and 1963.

Bogaert, for his part, told a journalist at the time that he had evidence that straight men exaggerate just as much as gay men. That would weaken the exaggeration argument, but it does not answer the others, and it was not published as part of the study.

Has anyone checked?

In over a quarter of a century, we found no study that compared gay and straight men measured the same way by a clinician. The closest thing is a 2002 study of 312 gay men who measured their partners with paper strips: their average erect length came out at 15.3 cm6 in, well above the clinic average of 13.1 cm5.2 in. But there was no straight comparison group, the measuring was done at home, and the men volunteered. It shows the same inflation as other self-measured samples, not a gay advantage.

A 2021 review of average size noted exactly this pattern: older self-report studies gave averages of about six inches for heterosexual men and even more for gay men, and the author attributed both to volunteers and to flattering answers rather than to biology.

The verdict

Gay men reported bigger cocks in one large, old, self-measured sample. That is all the evidence says. It might reflect a real difference, it might reflect who volunteered and how they measured, and without a modern study with a ruler in a neutral hand, nobody can tell. If it exists, the gap is under a centimetre, smaller than the difference between measuring from the skin or from the bone (see How to measure).

So enjoy the headline, but do not expect it at the next hookup. The man in front of you, gay or not, is most likely close to the average in Length.