Topic summary
Endogamous

Extracted from the Wikipedia article Endogamy.
Endogamy is common in many cultures and ethnic groups. Several religious and ethnic religious groups are traditionally more endogamous, although sometimes relationships outside of the group occur with the added dimension of requiring marital religious conversion. This permits an exogamous marriage, as the convert, by accepting the partner's religion, becomes accepted within the endogamous group. Endogamy may result in a higher rate of recessive gene–linked genetic disorders.