The hypothesized hormonal control of offspring sex ratio: evidence from families ascertained by schizophrenia and epilepsy.

Schizophrenic women reportedly have significant excesses of daughters. People with convulsions or seizures reportedly have excesses of brothers. And photosensitive probands reportedly have excesses of sisters. Steroid hormones affect neurotransmission in the brain. So these curious sex ratios are construed here as support for my hypothesis that parental hormone levels around the time of conception partially control the sexes of the resulting offspring.