Genetic and gender influences on nocturnal bladder control--a study of 2900 3-year-old twin pairs.

OBJECTIVE

The present study of over 2900 twin pairs born in England and Wales in 1994 examines the influences of genetics and gender on nocturnal bladder control at 3 years of age.

MATERIALS AND METHOD: Parent report data was analysed in terms of means and components of variance, using a sex-limitation model to explore genetic and environmental variation within and between the sexes.

RESULTS

Both genetics and gender are seen to influence acquisition: bladder control at 3 years is moderately heritable (24%), and girls show on average slightly increased acquisition compared with boys, even within opposite-sex pairs. The sex-limitation modelling showed an interaction between genetic influence and gender whereby nocturnal bladder control was significantly more heritable in boys (33%) than girls (10%).

CONCLUSIONS

Both genetics and gender are important and interacting factors in the aetiology of nocturnal bladder control.