In his book the history of sexuality (1978), michel foucault contends that the classification of homosexuality as a kind of deviance was a result of:

Accordidng to Michel Foucault, The result of homosexuality as a kind of deviance -- the rise of scientific ways of thinking and classifying, which included classifying humans.

people actually started talking about sex, whereas before sex talk was considered “impolite.”

government bureaucrats were attempting to assert their power over people

Now, since the society is more lenient to such oppression, homosexuality is not considered as a kind of deviance anymore.

Michael Foucalt's classification of homosexuality as a kind of deviance and by the help of his published book, entitled "History of Sexuality (1978), caused the rise of gay pride in different parts of the world and also caused the institution of gay marriage legislation.