Covid-19 is hugely infectious, spreading across the globe in a few short months. It’s thought to be spread through tiny droplets expelled from the mouth when an infected person coughs or sneezes.

But researchers at the University of Utah say that the possibility that coronavirus might be sexually transmitted can’t be completely ruled out.

Dr James M. Hotaling, a co-author of the study and associate professor of urology specialising in male fertility, that it’s only a remote possibility at this point: ”The fact that in this small, preliminary study that it appears the virus that causes Covid-19 doesn't show up in the testes or semen could be an important finding.

He added: "It could be that a man who is critically ill with Covid-19 might have a higher viral load, which could lead to a greater likelihood of infecting the semen.

"We just don't have the answer to that right now."

The virus has been conclusively identified in victims’ testicles, but as yet not in sperm. But if the virus could get into a man's sperm, scientists cannot definitely say a woman could not be infected by it.

Semen samples collected from 34 coronavirus patients in China Laboratory tests did not appear to contain any signs of the virus.

Jingtao Guo, a professor from the Huntsman Cancer Institute at the University of Utah and a co-author of the study, said: "If the virus is in the testes but not the sperm it can't be sexually transmitted.

"But if it is in the testes, it can cause long-term damage to semen and sperm production."

Researchers say that the possibility that the virus might be sexually transmitted can’t be completely ruled out

Since testicles are walled off from the rest of the body's immune system, the virus can stay there for longer periods of time, according to a study conducted at the Montefiore Medical Center in the Bronx, New York.

That phenomenon explains why the virus tends to take a much worse toll on men. But just as the virus that is responsible for Dengue fever appears to have become transmissible through sex, the possibility remains that Covid-19 can do the same thing.