The research, conducted by the University of London, found that 30 of 37 pesticides used widely in agriculture either blocked or mimicked male hormones. The researchers involved in the study are urging that further testing be conducted to determine whether the chemicals specifically target or block testosterone, which is critical to male sexual reproductive development. Read an article about the study here.

The findings are sure to get people taking another look at some troubling trends already spotted around the world. Male sperm counts are in decline and male fertility rates are dropping in many countries. Earlier research has suggested a link between some of these chemicals, labeled endocrine disruptors (for their impact on our hormone systems), and various sexual defects and reproductive health issues.

News reports on the study highlight that 16 of the 30 pesticides found to have an effect on male hormones were not previously known to be problematic, meaning we were unaware of any danger. But what may be even more troubling is that 14 of the pesticides were already known to have some effect on male hormones – and are still allowed in agricultural use.

The truth is we simply don’t know enough about the potential effects of many of these chemicals and the path to knowledge is long and expensive. The EPA’s Endocrine Disruptor Screening Program, designed to force the testing of pesticides and other chemicals found in drinking water and the food supply to determine the presence of hormone altering agents, has been slow to start, expensive and criticized by both the pesticide industry and environmentalists.

So, where to turn, until we learn more? The safest route would seem to be choosing organic when possible. But not all produce is equal – some conventional fruits and vegetables are dirtier than others. The Environmental Working Group has a handy guide noting the Dirty Dozen, the twelve fruits and vegetables that commonly carry the most pesticide residue. You can find that guide here.