The relationship between mothers’ and their daughters’ family size emerged in the United States during the 19th century
For more than a century, a key question of the social sciences has been whether daughters’ family sizes relate to their mothers’ family sizes. Contemporary evidence confirms that, in developed countries, women from larger families indeed tend to have more children themselves. There is considerable doubt, however, whether intergenerational continuity in childbearing constitutes a universal feature of human societies. Based on a large-scale web-harvested collection of online memorials, we show that intergenerational continuity in childbearing in the U.S. emerged only in the first half of the 19th century, paralleling the country’s marked fertility decline. Furthermore, we show that statewide differences in intergenerational continuity in childbearing coincide with statewide differences in abortion laws. This suggests that control over individual fertility was a major driver of the emergence of intergenerational continuity in childbearing. This finding suggests that, although intergenerational continuity in childbearing has appeared only relatively recently in the history of humankind, it will eventually become relevant worldwide.