Previous developmental research has found that children from households with high shared parenting, childrearing agreement, and equitable division of parental labor experience positive developmental and social outcomes; a major limitation of these studies is that shared parenting measures do not assess the amount of total parental effort the child receives, but instead partitioning the amount of effort between parents. Life History (LH) theory predicts that the total amount of parenting the child receives should produce a greater developmental impact on the future LH strategies of children than precisely how that parental effort was apportioned between mothers and fathers. This report presents a cross-cultural study using convenience samples of university students in Mexico, the United States, and Costa Rica, investigating the relationship of total as well as shared parental effort on family emotional climate and the LH strategy of the participants as young adults. The first study was performed exclusively in Mexico; results indicated that higher levels of shared parenting experienced as a child were associated with Family Emotional Climate also during childhood and with participant adult LH. The second study extended these findings; higher total parental effort predicted shared parenting effort, positive emotional climate, and slower offspring adult life history strategy in the three convenience samples of Mexico, the United States, and Costa Rica.