Zmiana płci „na słowo”. Praktyczne implikacje hiszpańskiej Ley Trans

On 1 March 2023, the so-called Trans Law (Ley 4/2023, de 28 de febrero, para la igualdad real y efectiva de las personas trans y para la garantía de los derechos de las personas LGTBI) came into force in Spain. This paper is a discussion on the political background and main ideas of the bill, and an analysis of its practical social implications and major controversies. The most important point of the bill is the introduction of the principle of self-declaration or legal gender self-determination, which de facto changes the criterion of sex in law from a physical one to a purely subjective and immaterial one, with far-reaching implications not only for women’s rights, but for the entire legal system.