Gender-critical feminism, also known as trans-exclusionary radical feminism (TERF) or TERFism, is an ideology or movement that opposes what it refers to as "gender ideology". Gender-critical feminists believe that sex is biological, immutable, and binary, and consider the concepts of gender identity and gender self-identification to be inherently oppressive constructs tied to gender roles. They reject transgender identities; for example, they describe trans women as men.
Originating as a fringe movement within radical feminism mainly in the United States, trans-exclusionary radical feminism has achieved prominence in the United Kingdom and South Korea, where it has been at the centre of high-profile controversies. It has been linked to promotion of disinformation and to the anti-gender movement. Anti-gender rhetoric has seen increasing circulation in gender-critical feminist discourse since 2016, including use of the term "gender ideology". In several countries, gender-critical feminist groups have formed alliances with right-wing, far-right, and anti-feminist organisations.
Gender-critical feminism has been described as transphobic by feminist and scholarly critics.. It is opposed by many feminist, LGBT rights, and human rights organizations. The Council of Europe has condemned gender-critical ideology, among other ideologies, and linked it to "virulent attacks on the rights of LGBTI people" in Hungary, Poland, Russia, Turkey, the United Kingdom, and other countries. UN Women has described the gender-critical movement, among other movements, as extreme anti-rights movements that employ hate propaganda and disinformation.