In 2006, the Portuguese parliament enacted a law (Lei da Paridade) which established a quota for female candidates on party lists. This increased the number of women in the legislature. In this paper, we analyse the impact of the reform on the behaviour of female MPs using data on bill co-sponsorship from 1991-2015. In particular, we analyse whether a) Female MPs are more likely to co-sponsor bills after the reform, b) Whether all female sponsored bills are more prevalent, and c) Whether female MPs are more likely to be co-sponsors on issues perceived as female. We find that the percentage of female MPs cosponsoring bills increases, albeit less so than for their male colleagues. The reason is the differential impact of the quota on internal party competition. Female MPs are not more likely to co-sponsor all female bills. Female MPs are also not more likely to co-sponsor on female issues. This suggests that the quota helped women to be represented, but that the traditional party dominance and agenda control remained strong constraints of legislative activities of female MPs.
