or abnormalities of central v asopressin receptor sensitivity, and reduced functional blad-
der capacities with bladder hyperreactivity (unstable bladder syndrome). Nocturnal en-
uresis is a genetically heterogeneous disorder. Heritability has been shown in family, twin,
and segregation analyses. Risk for childhood nocturnal enuresis is approximately 3.6 times
higher in offspring of enuretic mothers and 10.1 times higher  in the presence of paternal
urinary incontinence. The risk magnitudes fo r nocturnal enuresis and diurnal incontinence
are similar.