The oedipal period is reconsidered from the point of view of the various anatomical and physiological differences between the sexes at that stage of development. The difference in orgastic capacity of oedipally aged boys and girls is considered. Hypotheses are drawn regarding the implications of these differences in the development and nature of object relations, the sense of reality, and later adult sexuality. An additional aspect of the resolution of the oedipal situation is postulated for girls. These hypotheses are used in an attempt to help understand the positive results obtained by Masters and Johnson in their sexual therapy program.