Effects of bis(2-ethylhexyl) phthalate (DEHP) on secondary sex ratio of mice in a cross-mating study

Bis(2-ethylhexyl) phthalate (DEHP) was given in the diet to provide levels of 0 (C) or 0.03% (T) from 5 weeks of age of the F0 generation to birth of the F1 generation in mice. At 9 weeks of age, each female was paired with one male from the same or another treatment groups (cross-mating: C/C, T/C, C/T, T/T), for a period of 5 days. The males were removed from females after 5 days, and the females were allowed to carry their litters to term and deliver. There were no adverse effects of DEHP on either litter size, litter weight and sex ratio at birth. The average body weight of male offspring was significantly increased in all treatment groups at birth. There were no adverse effects of DEHP on female offspring weight at birth. The dose level of DEHP in the present study produced no adverse effects on secondary sex ratio, which meant sex ratio at birth, in mice.