Numerous studies have suggested dangerous effects from pesticides, but now researchers have discovered the first link between pesticides and a lower quality of semen.

The study, published in the journal Human Reproduction found that men who ate the largest amount of fruits and vegetables with high levels of pesticide residue had a 49 percent lower sperm count and a 32 percent lower percentage of normally-formed sperm than men who consumed the least amount of produce with pesticides.

Dr. Jorge Chavarro, study author and assistant professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health in Boston, told FoxNews.com he was surprised at the significant effect of pesticide consumption on sperm count.

“While previous work had linked occupational exposure to pesticides to impaired sperm production I was skeptical that pesticide residues in food could have a similar effect,” Chavarro said. “I think this study opened a lot more questions than I had anticipated.”

Chavarro’s team analyzed 338 semen samples from 155 men over five years who attended a fertility center. Participants ranged from 18 to 55 years old and completed food frequency surveys. Researchers used the annual United States Department of Agriculture Pesticide Data Program to categorize various fruits and vegetables as being high, moderate, or low in pesticide residue. They also took into account common food preparation practices, like peeling or washing.

High residue foods included peppers, spinach, strawberries, apples and pears, while some low residue foods were peas, beans, grapefruit and onions. 

The men who consumed the most pesticide-heavy fruit and vegetables had an average total sperm count of 86 million compared to men who ate the least amount, with an average sperm count of 171 million.

Researchers said poor semen quality is the leading cause of unsuccessful attempts to achieve pregnancy and one of the most common medical problems among young men. Semen production is very sensitive to environmental exposures and lifestyle factors, leading scientists to believe it is an accurate marker for both morbidity and mortality.

However, findings also showed that men who consumed the most fruit and vegetables with only low-to-moderate pesticide residue had a higher rate of normally shaped sperm, proving the health benefits of a plant-based diet. 

Chavarro said although the study yielded significant results, he thinks more research that provides additional evidence of harm is needed before changes are made in agricultural pesticide guidelines or restrictions.

“I think it is important that these results are replicated in other studies, as it is also important to determine whether the effects on sperm quality translate into observable effects on fertility,” he said.

In the meantime, he said men shouldn’t let the study results dissuade them from eating fruits and vegetables, but maybe consider consuming organically-grown produce or avoiding produce that is known to have a high amount of residue.