The events and tempo of mammalian meiosis show sexual dimorphism with gametogenic context having a significant influence on both chromosome dynamics and cell cycle transitions. However, although some regulators of the meiotic cell cycle may differ between males and females, there appears to be extraordinary conservation of key components in common with the mitotic cell cycle and between sexes in meiosis. Evidence is presented for the existence of meiotic checkpoints that might modify or ameliorate cellular error or damage by reproductive toxins. Although these checkpoints seem relatively inefficient, they may be more so in female meiosis than in male meiosis. Insight into mechanisms of meiotically acting reproductive toxins coupled with genetic models will ultimately bring about understanding of the basic mechanisms of meiotic cell divisions and chemically induced meiotic error.