MODERN life is putting the future of the human race "in jeopardy" - by destroying men's sperm, experts have warned.

The quality of sperm is falling by almost two per cent every year because men are eating too much junk food and not exercising enough, new research suggests.

The decline has been noted among sperm donors and men seeking fertility treatment.

Two studies to be presented at the annual conference of the American Society for Reproductive Medicine, in Denver, Colorado, this week show declines in sperm swimming ability as well as count.

Doctors believe obesity and our sedentary lifestyles are contributing to the fall, as well as exposure to dangerous toxins in air pollution, according to The Times.

Last year experts warned sperm counts had dropped 60 per cent in the last 40 years, prompting fears it could lead to the extinction of the human race.

For the first study researchers looked at data from more that 124,000 sperm samples in six cities across the US, collected between 2007 and 2017.

The team from the Icahn School of Medicine at Mount Sinai and Reproductive Medicine Associates, both in New York, found sperm count; sperm concentration; and sperm's swimming ability was declining.

In the second study, experts from the US and Spain took samples from 120,000 men being treated for infertility between 2002 and 2017.

In 2002 some 85 per cent of men tested had a high healthy sperm count, but by 2017 it had dropped to 79.1 per cent.

The number of men with the lowest sperm count - and least healthy sperm - rose from 8.9 per cent to 11.6 per cent in the same years.

James Hotaling, a co-author of the study from the University of Utah, said: "Male infertility is under-recognised and these results are a cause for concern.

"We did not expect to see the same fall in sperm quality in Spain and the US but, whatever we did in the study, it didn't go away.

"If this trend continues, there is potential for more men to become infertile and that is concerning when it takes two people to make a child."

Charles Kingsland, clinical director of Care Fertility, and professor of reproductive medicine at Edge Hill University in Ormskirk, Lancashire, added: "Our change to a more sedentary lifestyle has no doubt had an effect, as has our diet because men tend to eat far more rubbish than they did a generation ago.

"But although sperm counts are declining, we do not know whether that affects the ability of the sperm to create a pregnancy."