The anti-gender movement is an international movement which opposes what it refers to as "gender ideology", "gender theory", or "genderism". These concepts do not have a coherent definition and cover a variety of issues; "gender ideology" has been described as an "empty signifier" or catch-all term "for all that conservative Catholics despise". The movement derives from Catholic theology beginning in the 1990s, but the protests which brought the movement to attention did not start until around 2012–2013. It often includes opposition to same-sex marriage and transgender rights.