“These findings provide the first direct experimental evidence that the male reproductive system could be targeted and damaged by Covid-19,” the authors concluded.
Experts commenting on the research, however, said the capacity of the virus to compromise fertility in men remains unproven.
Covid-19 causes respiratory illness, especially in older people and those with underlying medical problems.
The world has seen more than 100 million confirmed cases since the disease emerged in central China at the end of 2019.
Transmitted through respiratory droplets, the disease attacks the lungs, kidneys, intestines and heart.
It can also infect male reproductive organs, impairing sperm cell development and disrupting reproductive hormones, earlier studies have shown. The same receptors the virus uses to access lung tissue are also found in the testicles.