Transgeneration analyses of the human sex ratio: the influence of combinations and permutations of sexes of children on family size.

Transgeneration analyses, involving the parental, present, and projected generations, were made of the human sex ratio and the influence of combinations and permutations of sexes of children on family size in a population of Western Kentucky University students and their families. The investigation included some previously studied characteristics of the population. The general conformity of the results, previous and present, suggests a high degree of repeatability within the findings. Secondary sex ratios (males: 100 females) were 106.4, 101.2, and 133.3, respectively, for the parental, present, and projected generations. Corresponding average family sizes were 4.73, 3.70, and 2.80 children. A higher percentage of one-child families included both sexes with the male being first-born, and more two-child families consisted of two males rather than two females. The two-child (male-female order) family occurred more frequently than any other family regardless of size, combination, or permutation of sexes.