Scientists say that there is increasing evidence in patients of testicular damage and lower sperm counts and mobility, with initial studies revealing the presence of the virus in semen samples.

Researchers at the Justus-Liebig-University in Germany. along with scientists from Allameh Tabataba'i University in Iran have reported  significant inflammation markers in samples of testicular tissue from 84 Covid-19 patients.

They discovered that the inflammation and cellular stress were twice as severe in the Covid-19 positive group as in a control group.

Researchers also noted that sperm was three times slower in COVID patients, and sperm count in general was much lower.

The study found that sperm concentration was reduced by 516 per cent, mobility by 209 per cent and sperm cell shape was altered by 400 per cent.

The researchers further noted that this represents oligoasthenoteratozoospermia, one of the most common causes of subfertility in men.

"These effects on sperm cells are associated with lower sperm quality and reduced fertility potential," noted lead researcher Behzad Hajizadeh Maleki.

"Although these effects tended to improve over time, they remained significantly and abnormally higher in the Covid-19 patients, and the magnitude of these changes were also related to disease severity," Maleki further warned.

In addition, Researchers from the Huazhong University of Science and Technology in Wuhan (yes, that Wuhan) have issued a call for a long term study into the effects of the virus on male fertility.

"We propose that there is an urgent need to track male Covid-19 patients during their recovery," microbiologist Yu Tian and reproductive biologist Li-quan Zhou noted.