PRESIDENTS PREFERRED SONS

Trivers and Willard (1973) argued that, in polygynous species, parents ''in good condition'' should bias investment toward sons, while parents ''in poor condition'' should bias investment toward daughters, Biographical evidence on men in the U.S. executive branch-including presidents, vice presidents, and cabinet secretaries-suggests they produced more sons than daughters in the first cohort (Presidents Washington through Garfield), but roughly equal numbers of sons and daughters in the second cohort (Presidents Arthur through Reagan). The same pattern holds for presidents' fathers and sons, Presidents' wills reflect the pattern again: men in the first cohort (Washington through Garfield) favored their sons, overall, slightly more than their daughters; for men in the second cohort (Arthur through Reagan), that bias disappears.