Homosexuality is considered in Catholic Church teaching under two distinct aspects. Homosexuality as an orientation is considered an "objective disorder" because seen as "ordered toward an intrinsic moral evil", but not as sinful. "Homosexual activity" is seen as a "moral disorder" and "homosexual acts" as "contrary to the natural law. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity."The Catholic Church believes that marriage can only be between a man and a woman, and opposes introduction of same-sex marriage.