Starting from these experimental observations, showing that simazine can impair several differentbiological mechanisms, here we document that this compound, even at low doses, impairs swinegranulosa cell function, possibly resulting in reproductive dysfunction.Rich et al. (2012)reported similar effects on human breast cancer cell lines, hypothesizing an association betweensimazine stimulatory action on cell growth and the presence of estrogen receptor. This evidence concerns the gene ESR1 and breast carcinoma.