Factors Influencing the Frequency of Consanguineous Marriages in Japan: Marital Distance and Opportunity of Encounter

Abstract

The inbreeding coefficients (F) were estimated according to marital distance between birthplaces and the opportunity of encounter. As for marital distance, the F-value was the highest for the shortest distance (0.00252), whereas the F-values were similar in the other distance classes (0.00072-0.00097). As for opportunities of encounter, the F-value was 30-37 times higher in the group for friendship from the time of childhood (0.00986) than in those for school, workplace and social gatherings (0.00033) and for chance meetings (0.00027).