In opposition, some feminists believe sex positivity perceive disadvantage in women, but makes them easier to oppress . Some, largely religious and particularly Judeo-Islamic-Christian, conservative opposition to sex-positivity sees human sexuality as a destructive force except under the contract of a marriage. Sexual acts are ranked hierarchically, with marital heterosexuality at the top of the hierarchy and masturbation, homosexuality, and other sexualities that deviate from societal expectations closer to the bottom. Medicine and psychiatry are said to have also contributed to sex-negativity, as they may designate some forms of sexuality that appear on the bottom of this hierarchy as being pathological "(see Mental illness)".