Note (return) — ORGANIC DIFFERENCES IN THE SEXES

Observations of above 4,000 cases show that, among horses, the more the parent animals differ in color, the more the female foals outnumber the male. Similarly, in-and-in-bred cattle give an excessively large number of bull calves. Liaisons produce an abnormally large proportion of females;20 incestuous unions, of males.21 Among the Jews, who frequently marry cousins, the percentage of male births is very high.