The Detection of Genetical Influences on Human Family Size

Abstract

The genetics of human family size is not readily susceptible to analysis. Some of the problems in its investigation are discussed, together with methods for overcoming them. In particular, the problem of obtaining a satisfactory model which will account for both the low heritability of family size and its over-dispersed distribution is examined in detail.

Models of Parent‐Offspring Conflict in Small Populations

“…1 2 A number of workers (e.g. TRIVERS, 1974;ALEXANDER, 1974;ZAHAVI, 1974) have considered the possibility that parent-offspring interaction ("interference") may act to mitigate the harmful effects of "selfish" offspring upon their "altruistic" sibs. Opposing conclusions have been reached about the possibility of increase of genes promoting "interference" as against "quiescence", or ('altruism" as against ('selfishness", Trivers concluding that parent-offspring "conflict" may arise if some offspring are "selfish" rather than "altruistic", Alexander that "selfish" genes cannot spread because their ca.rriers will have diminished reproductive success, despite their earlier ('selfish" advantage.…”