Consanguineous Marriages in the American Population

A measured examination of kin marriages in early‑twentieth‑century America, this study gathers fragmentary yet insightful statistics from census reports, genealogical records, and contemporary scientific inquiries. The author lays out the range of consanguinity—from distant cousins to close relatives—while weighing competing theories about its influence on sex ratios, fertility, and the prevalence of certain health conditions. By drawing on contributions from notable scholars and physicians of the era, the work presents a balanced overview of the data then available without overstating its conclusions.

The second half of the book turns to the social ramifications, exploring how close‑blood unions intersect with questions of mental health, sensory impairments, and broader notions of eugenics and social evolution. Detailed case studies from isolated communities and larger population samples illustrate both patterns and anomalies, inviting readers to consider how statistical gaps shape public policy. Throughout, the tone remains cautious, acknowledging the limits of the evidence while highlighting the enduring curiosity surrounding genetic relationships in society.