Genetic basis of sex differences in the prevalence of asthma

The possibility that sex differences in the prevalence of asthma are caused by a genetic sex influence was investigated in 298 asthmatic patients with three or more positive skin tests (sex ratio=1.35) and in 94 asthmatic patients with no positive skin tests (sex ratio=0.58). The distribution of asthma among the male and female relatives of the male and female patients was uniform in both groups, indicating there was no genetic sex influence.