ABSTRACT
It is important to realize that both of the behaviors focused on in Wilson and Daly’s chapter-cohabitation and stepparenting-have been experiencing extraordinarily rapid change in incidence. Hence, analyses of unchanging biological underpinnings of human behavior, even those with direct measurement of the biological markers (Booth & Dabbs, 1993; Udry, 1994), although informative, are unlikely to help us understand the dynamics involved in these phenomena currently.
