Handedness and time to pregnancy.

Background: Nonright-handedness, particularly mixed-handedness, has been associated with a number of medical conditions. We examined whether handedness was associated with fecundity, measured by time to pregnancy.
Methods: We used data on parental handedness and time to pregnancy from 2 regional birth cohorts in Denmark: the Aalborg-Odense Birth Cohort (1984-1987) and the Aarhus Birth Cohort (1990-1992) (n = 5808 and 3426, respectively). We applied discrete-time survival analysis to assess fecundity in relation to handedness.
Results: In both cohorts, we saw a slightly lower fecundity in individuals who reported being mixed-handed.
Conclusions: Our data showed a modest association between mixed-handedness and subfecundity, which suggests that these traits may share a common etiology, perhaps tracing back to the prenatal period.