Incidence of left-handed writing in a college population with reference to family patterns of hand preference.

Hand preference data were obtained for 1816 university students, 4793 siblings and 3632 parents. Results support the following conclusions. (1) There is currently a 13.8% incidence of left handedness among young adults, representing a dramatic increase over past generations. (2) Left and right-handed respondents do not differ in terms of familial sinistrality. (3) Mother's left-handedness is associated with an increase in the incidence of sinistrality for sons and daughters, while father's left handedness is related only to sons.