Wilhelm Fleiss was the first to suggest the linkage between bilateralism and bisexuality, in which he posited a link between Cross-gender identification and a tendency to be left-handed. More recently, Geschwind and Galaburda (1987) have suggested the probable neuro-hormonal bases for such putative linkages. The present study compared the hand preference scores of young females with high masculine gender identity and low masculine gender identity. There was greater non-right handedness among the high masculine gender identified females. Family history of handedness was also found to affect individual handedness. Fleiss's early insight and Geschwind and Galaburda's more recent hypotheses thus find empirical support.