Completed forms containing the Edinburgh handedness inventory were received from 77 women exposed to diethylstilbestrol (DES) in utero. Laterality scores (LSs; range: -100 to +100) were calculated for each respondent based on the handedness inventory and were compared with LSs from 514 female controls. The handedness distribution in the DES daughters was significantly shifted away from strong righthandedness compared with the handedness distribution in the controls (chi-square = 22.0, P < 0.0001). Possible explanations for the association between handedness and DES exposure are presented, and aspects of handedness measurement are discussed.