Researchers in the United States have linked commonly used antidepressants to a reduction in some men's fertility.
The researchers from the Cornell Medical Center in New York say the drugs, selective serotonin-reuptake inhibitors (SSRIs), taken by millions of men to alleviate depression, damage the DNA of the sperm.
According to scientists Peter Schlegel and Cigdem Tanrikut the fertility of a substantial number of men on paroxetine may be adversely affected by these changes in sperm DNA.
In a study of 35 healthy volunteers who provided sperm samples before and during paroxetine treatment, it was found that, on average, the proportion of sperm cells with fragmented DNA rose from 13.8 percent before treatment to 30.3 percent after just four weeks.
Similar levels of sperm DNA damage have been linked to problems with embryo viability in couples trying to have children.
The new research supports concerns raised two years ago that men had developed low counts of healthy sperm following treatment with two different SSRIs.
SSRIs such as Paxil, Seroxat and Prozac are the most commonly prescribed class of antidepressant and drug manufacturers are apparently reviewing the study findings.
They say as these drugs are an important option for the treatment of depression, and patients should discuss their situation with their doctor before stopping use of their medication.
While experts say the study results are a concern they suggest a randomized controlled trial would be the most scientific way to investigate the drugs effects.
They say SSRIs are known to depress libido in some men and previous research has also found that women taking the medicines are more likely to have a low birth weight baby.
Mental health experts say most medications carry some level of risk, and antidepressants are powerful drugs and are in that respect no different.
The research is published in New Scientist and is due to be presented in November at a meeting of the American Society for Reproductive Medicine.