There has been little in-depth theoretical study in sociology of the motives of women and men who are childless by choice. This article begins to remedy this deficiency by analyzing the motives articulated by twenty-three childless women and men using Weber's typology of social action and distinction between primary and end motives. In-depth interview and focus group data reveal that, compared to men, women more often were affected by the parenting models of significant others, saw parenting as conflicting with career and leisured identities, and claimed the lack of a “maternal instinct” or disinterest in children as dominant influences. Men more explicitly than women rejected parenthood because of its perceived sacrifices, including financial expense. Both women and men were motivated by personality traits that they deemed incongruent with good parenting. Declared motives especially demonstrated instrumentally rational action in Weber's schema, although affectual and value-rational actions also were present. Respondent motives are compared to those that they, and empirical studies, have attributed to parents.