The sex-ratio of children born to parents affected with Huntington''s disease

To examine a Pennsylvanian report that children born to mothers a decade before or after the onset of Huntington's disease tend to be girls, a study was made of sibships ascertained from the Victorian population. Although a trend was observed in the direction described, no significant result was obtained. When the effect of parental age on the sex-ratio was tested, the proportion of boys increased linearly with the age of the affected mother. The effect occurred for all children and for those to whom the disease was transmitted. Some possible mechanisms were discussed.