We examine two variations in the Irish Sign Language of Dublin, Ireland. Signers commonly refer to these sign varieties as “female” and “male” signs. Because of the historical link of these signs to school signs, the signers in this study were selected on the basis of age, sex, and social network. The sex of the signer seems to explain differences observed in the distributions of signers’ knowledge and use of the “female” and “male” sign varieties. We argue that the differences between women’s knowledge and use of “male” signs, and men’s knowledge and use of “female” signs result from differences in cultural opportunities to acquire full facility with both varieties.