Organophosphate and N-methyl carbamate pesticides used at residences and on food crops were associated with lower sperm counts, according to a study in Environmental Health Perspectives — and the higher the exposure, the greater the effect.

Two common classes of pesticides may be responsible for the 50-year-long drop in global sperm counts.

According to a paper in Environmental Health Perspectives, men with the highest exposure to organophosphate and N-methyl carbamate pesticides had sperm counts almost one-third lower than men in the lowest-exposure group.

During the last 50 years, sperm concentrations in human semen have dropped by 51.6%, and total sperm counts fell 62.3%. Low sperm counts reduce a man’s ability to father children.

‘Strength of evidence warrants reducing exposure’