The author describes a study that investigated what three-and four-year-old girls and boys know about the link between genital difference and gender difference by asking them to construct both a girl doll and a boy doll, using any of an assortment of anatomical features, including both male and female genitals. The results were interpreted as supporting the assumption of a normal early developmental period of psychological bisexuality; as contradicting the theory that when genital difference is discovered, girls are more distressed than boys about their genitals; and as evidence that both girls and boys envy the genital of the opposite sex.