We examined whether the risk of poor semen quality increased when men were exposed to more than one of the five “associated pesticides”.  To do this, we defined a pesticide score to which we added 1 whenever the man’s exposure to alachlor, diazinon or metolachlor was high, or if he had detectable levels of atrazine or 2, 4-D.   Therefore, the score for each man ranged from zero to five.  

All men with a score of zero were controls and only cases of poor semen quality had a score of 3 or more. Thus, there was a significantly increased risk of poor semen quality with increasing number of pesticide exposures.