Movie S2.

Sexual behavior of gonadally intact wild-type and PgrΔ136E1 null female rats. Representative interactions of wild-type and PgrΔ136E1 null female rats with sexually experienced male rats. Female rats were staged by daily assessment of vaginal cytology and placed with males during the evening of proestrus. The first interaction shows a gonadally intact wild-type female (+/+, No. 38) exhibiting lordosis when exposed to a male. The second and third interactions are between PgrΔ136E1 null females (−/−) and males. In the second interaction, a PgrΔ136E1 null female (−/−, No. 89) allows the male to mount but does not show complete lordosis, whereas in the third interaction a different PgrΔ136E1 null female (−/−, No. 53) is rejecting attempts of the male to mount.