Size Does Actually Matter When It Comes To Male Fertility, Study Finds

There's only a centimetre in it.

We’ve long been told it’s not about your size, it’s about what you do with it, but new research has found that penis length could matter if you’re hoping to become a father.

Scientists found a direct correlation between men with fertility problems and those with shorter penises. But not by much: a mere 1cm difference notably decreased fertility prospects.

So those with an average length of 13.4cm were less likely to have reproductive issues than those with a penis length of 12.5cm.

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The University of Utah study – to be presented at the American Society for Reproductive Medicine’s conference – was based on data from 815 men visiting a clinic that deals with infertility, erectile dysfunction and testicular pain.

When the men presented at the clinic, they were measured using a test called “stretched penile length” that estimates length when erect. This data was then correlated against the issues they were experiencing.

It may come as a surprise that such a small difference in size changed fertility prospects. Dr Austen Slade, who led the study, said: “One centimetre may not be a striking difference but there was a clear statistical significance.

“It remains to be determined if there are different penile length cut-offs that would predict more severe infertility.”

Dr Slade speculated that the cause behind the link may be a manifestation of congenital or genetic factors that predispose someone to infertility.

So what can men do about this? Sheena Lewis, an expert in reproduction from Queen’s University Belfast, says men should not worry. “One thing that scares men is that size matters. To now say they have a smaller chance of becoming a father is not a good message,” she said.

“Doctors would not want to measure this in clinic, so as a study the findings are not really clinically usable. This is a very novel idea, but the study does not tell us what a normal penis length is.”

In the meantime, other research, presented at the same conference, found men could improve their fertility chances by avoiding detrimental environmental factors: smoking, stress, obesity and exposure to chemicals in plastic.

Semen quality is getting worse as a result of these factors – the rate of men being treated for infertility has increased 700 per cent in the past 15 years, while sperm counts among men living in western countries have fallen by 59.3 per cent in four decades.