Sperm Competition and Sexuality Myths

A web talk show in Halifax once featured a psychology professor who teaches a university course on human sexual behaviour. The conversation moved across several topics that regularly surface in sexuality classes: sperm competition, grooming trends, the vocabulary of oral sex and the effects of pornography. Each one comes with scientific debate, and the claims made in the interview illustrate how popular accounts and research can diverge.

Sperm competition

Sperm competition is a real field of evolutionary biology. It studies what happens when sperm from different males are present in the same female reproductive tract, and it has produced many findings in insects, birds and mammals. In the interview, the professor presented the topic as a way of bringing evolutionary biology into a course on sexuality.

The talk also repeated a vivid popular version known as the kamikaze sperm hypothesis, in which a small share of sperm fertilize while the rest attack rivals or block them. That idea dates from the 1980s, and later work has questioned whether it describes human reproduction. Scholars generally treat the colourful sports metaphors as storytelling rather than settled science.

The same segment cited a figure of up to ten per cent of children not being fathered by the men believed to be their fathers. Studies of misattributed paternity have usually reported lower rates, often in the low single digits, though they vary by population and method.

Pubic hair and changing norms

Grooming practices have shifted over the past few decades. The professor pointed to the full styles seen in magazines of the 1970s and 1980s, in contrast with the heavily waxed looks associated with later pornography, and said waxing aimed at men had become more common. She also advanced an evolutionary explanation for preferences about hair and fertility, a theory that remains speculative. Another claim, that hair on men adds stimulation during certain positions, rests on anecdote rather than established research. Cultural historians usually link grooming trends to fashion, media and hygiene norms.

Vocabulary and sex education

The professor observed that many of her students used the word for oral sex performed on a man to cover every kind of oral sex, and did not know the word for oral sex performed on a woman. She read this as a sign of weak sex education and of lingering discomfort about female pleasure. Similar arguments appear in research on the so-called pleasure gap in sexual health teaching.

Pornography and desensitization

The professor suggested that heavy pornography use can dull responsiveness to ordinary partnered sex and push some viewers toward more extreme material, an idea she called a slippery slope. Researchers disagree. Some studies link frequent use with lower satisfaction, others find little effect, and the term addiction itself is contested in the clinical literature. Because these topics mix biology, culture and personal values, readers meet widely differing conclusions depending on the source.