Turkey has a high rate of consanguineous marriage (21.1%); indicating
strong preference for this traditional form of marital union. Social a
nd cultural factors are especially important in marriages between firs
t and second cousins. Fertility is high, the closed birth interval is
long, and the sterility rate is low among these couples. Post-neonatal
, infant and under-5 mortalities are high in first cousin unions by co
mparison with non-consanguineous marriages. According to the results o
f the study, first cousin marriage is a significant determinant underl
ying the high total fertility and infant mortality rates in Turkey.