New study says that men who smoke cannabis could have a higher sperm count

New study says that men who smoke cannabis could have a higher sperm count
A new study found that those with a previous history of smoking cannabis had a higher sperm count than non-users (Photo: Shutterstock)

Men with a history of smoking cannabis may be more fertile than those who have never touched the drug, according to a new study.

Scientists measuring the sperm counts of more than 600 men from couples attending a fertility clinic found that those who had previously smoked cannabis had a higher sperm count than non-users.

A survey spanning 17 years

The scientists who conducted the study expected the use of cannabis to have a detrimental effect on sperm count and therefore have an impact on fertility, but the results revealed the opposite.

For this study, investigators collected 1,143 semen samples from 662 men between 2000 and 2017.

On average, these men were 36 years old and all of them belonged to couples seeking help with conception from a fertility clinic.

Significantly higher sperm counts

Participants were asked to fill in questionnaires which detailed their history of cannabis use, with more than half (55 per cent) of the men reporting that they had smoked cannabis at some point in their lives. Of those who reported cannabis use, 44 per cent said they had taken the drug in the past, with 11 per cent classifying themselves as current users.

Analysis of the semen samples showed that men who had smoked marijuana had average sperm concentrations of 62.7 million sperm per millilitre (million/mL), while those who had never smoked cannabis had an average count of 45.4 million/mL.

Only five per cent of cannabis users had sperm counts below 15 million/mL, which is the World Health Organisation’s threshold for ‘normal’ levels.

Although those conducting the study expected the use of cannabis to have a detrimental effect on sperm count, the results revealed the opposite (Photo: Shutterstock)
Although those conducting the study expected the use of cannabis to have a detrimental effect on sperm count, the results revealed the opposite (Photo: Shutterstock)

In addition to this, greater cannabis use was also linked to higher levels of the male hormone testosterone among smokers.

‘Results need to be interpreted with caution’

Writing in the journal Human Reproduction, the scientists said that it was possible that low level exposure to cannabis might benefit sperm production in some way.

However, authors of the study and other experts also pointed out that the findings do not necessarily equate smoking cannabis to an increase in the chances of fatherhood.

There could be a non-causal explanation for this association, such as the effect of the male hormone testosterone on both sperm count and risk-taking behaviour, such as smoking cannabis.

US lead researcher Dr Jorge Chavarro, from the Harvard TH Chan School of Public Health in Boston, said, “These unexpected findings highlight how little we know about the reproductive health effects of marijuana, and in fact of the health effects of marijuana in general.

“Our results need to be interpreted with caution and they highlight the need to further study the health effects of marijuana use.”