First, Foucault identifies a very different motive than simple repression at work in the study of child sexuality. The scrutiny of children's sexuality effectively serves as a launching pad for a more general examination of sexuality. It alerts parents, teachers, and doctors to the dangers of child sexuality, and traces the origins of child sexuality in family relationships. What is made to seem like a boundary—excluding children from the realm of sexuality—is essentially a means to expand the study of sexuality to a number of different realms.
Second, Foucault sees the modern concept of homosexuality arising from a desire to see sexuality as a fundamental aspect of who we are. Before the 19th century, sodomy was simply regarded as a criminal act. Since the 19th century, sodomy has been regarded as just one manifestation of a person's homosexuality. "Homosexuality" ceased to be associated with certain acts, and became associated with a person's identity, with his soul. One's sexuality became a key to interpreting one's personality and one's behavior. Rather than work to eliminate homosexual acts, the growing discourse around homosexuality saw these acts as constitutive of a person's identity.
Third, Foucault sees the increased scrutiny on different forms of sexual behavior as part of what he calls "spirals of power and pleasure." The close scrutiny that accompanies the "medicalization of sexuality" draws observer and observed into intimate contact. On one hand, the observer exercises power in examining and drawing out his subject's sexual pleasures, and this exercise of power gives him a kind of pleasure. On the other hand, the observer's scrutiny isolates and highlights his subject's pleasures, thus encouraging them. Both observer and observed find power and pleasure intermingled in this intimate game of examination.