A possible explanation for digynic triploidy after superovulation is briefly discussed. It is suggested that digynic triploidy may be closely related to the aging of eggs at fertilization rather than gonadotropin-induced superovulation. It is known that aging of eggs results in a decrease in the fertilization rate an increased incidence of abnormal fertilization and subsequent degeneration of embryos. Since the time of ovulation for each egg would be more spread out during superovulation than normal ovulation one would expect an increased frequency of digynic triploidy following superovulation.