“…This peak in the incidence of kin marriage was followed by a regular or abrupt decline to some point in the 1950s or 1960s when such marriages became almost non-existent. Strikingly, the growth and decline of kin marriage occurred almost simultaneously in highly different localities and regions across Catholic and Protestant Europe and America (Bittles and Egerbladh, 2005;Bittles and Smith, 1994;Bourgoin and Khang, 1978;Cavalli-Sforza et al, 2004;Deraemaeker, 1958;Gouesse, 1986;Hall, 1977;Ottenheimer, 1990;Pettener, 1985;Polman, 1951;Sabean, 1998;Saugstad, 1977;Smith, 2001;Sutter, 1968;Sutter and Lévy, 1959;Van Straaten, 1966Zei et al, 2005).…”