Gender-inclusive language is an important issue in the struggle for political equality between women and men. Parliaments are a central arena in this struggle as they both reflect and shape gender-relations in society. Based on a novel high-quality corpus of all its debates, we study the evolution of gender-fair language in the German national parliament, Bundestag, between 1949 and 2021. As a “gender language” with a grammatical gender, German offers ideal conditions to inspect semantically symmetric male and female forms of personal nouns. Our analysis of more than 2.5 million occurrences of 1,600 lemmas of personal nouns reveals that female forms had been virtually non-existent in legislative speech before experiencing a stark increase since the 1980s. This evolution has been driven specifically by the gender and partisan affiliation of MPs while there is little evidence for generational effects.