The long eighteenth century saw enormous upheavals and experimentations with gender, especially in theatrical practice. A group of female singers termed by Heather Hadlock as musicos played heroic, romantic leading men, often playing roles which had been written for the now out-of-vogue castrati. In examining the lives of these singers, this paper will look for intersections between Thomas Laqueur’s theorization of a shift from the one to two sex model and the performance of gender on the operatic stage.