the anonymous buccaneer Painting

Pirates rarely allowed women on their ships. They were considered bad luck and it was feared that the men on board would fight because of one. On many boats, the presence of women (just like that of young boys) was prohibited by the pirates' code which all crew members had to sign before boarding. This resistance to accepting women on ships did not allow many female pirates to come forward and most remained anonymous, acting on board under assumed names and cross-dressing in men's clothes. The two famous pirates Anne Bonny and Mary Read, for example, dressed and behaved like men. (wikipedia)