Masculine-looking men may have lower quality sperm - study

Men with wider-faces - a trait associated with masculinity - may have lower quality sperm, say researchers. Photo / 123RF

He might radiate masculinity with his square jaw and strong cheekbones.

But a macho face doesn't mean a man has macho sperm, according to new research.

Scientists have found that men with more masculine, wider faces tend to have poorer quality semen than their more feminine-faced counterparts.

Previous research has found that men with deep voices have lower sperm counts than their counterparts.

Experts say this could be because high levels of the male sex hormone testosterone impede sperm production.

However in the new study, the researchers also found that men rated as attractive (rather than macho) by both sexes have good quality sperm compared to those rated less attractive.

One theory is there is a 'trade off' in which masculine men with a deep voice and big muscles beat away the competition to attract more women, but may lose out on the virility front.

Because masculine men may attract more women, they may not need such good quality sperm to impregnate a woman.

As part of the new study, published in the Journal of Evolutionary Biology, a team of researchers from Spain, Australia and Colombia analysed the semen of 50 Caucasian students from the University of Valencia.

They then took photos of the men's faces, and scored them on seven parameters which indicate masculinity, including cheekbone width and nostril width.

Finally, they analysed whether there was a link between any of these indicators of masculinity and the quality of the men's sperm.

The researchers found that men with more masculine, wider faces tended to have poorer quality semen.

As well as wider faces being linked with higher testosterone levels, they have also been linked with traits such as aggressiveness, dominance, physical strength, status, financial success and deceptiveness.

However, the researchers admitted that when men with abnormal semen (defined by levels set by the World Health Organisation) were excluded from the study, the association disappeared.

The findings seem to contradict the 'phenotype-linked fertility hypothesis', in which it is believed that facial traits signal good health, and so females choose attractive men so their offspring might gain genetic benefits like health and intelligence.

The researchers also wanted to explore whether men with attractive, rather than just masculine, faces had better quality sperm.

So they took the photos of the men, added a black oval around their faces to minimise the visual effect of their hairstyle, and showed them to a group of 149 heterosexual women and 77 men.

The female judges were asked to rate each photograph for facial attractiveness on a scale of zero to ten, as if they were rating a potential long-term partner.

The male judges were asked to rate the photographs on how attractive they thought women would rate them as partners.

The study found that faces that were rated more attractive had higher sperm quality.

Researchers also revealed that men ranked the people in photos they saw as more attractive than women and that the Spanish raters gave higher scores than the Colombian raters.

- Daily Mail