Fig. 3.

This cartoon illustrates a sequential relationship between the two oestrogen receptors (ERs) during development. The white diamond represents ERβ, the black diamond represents ERα, and the grey triangle is oestradiol activating the receptors. (A) An illustration of the roles of ERβ activation in neonatal males followed by activation of the ERα in adult males. The end result of the two actions is defeminisation of adult male behaviour. (B) An illustration of the situation in a normal female. Here, the lack of ERβ activation in the neonatal period is responsible for the adult activational effect of oestradiol on lordosis.