Inter Family marriage can cause genetic disorders.
medical science proved that marrying within the family over generations can cause genetic mutations and there is a greater incidence of abnormalities in their children.
marriages between first and second cousins the chance is very high. This type of marriage is common in Middle-East countries and Pakistan there is a lot of genetic disorders are reporting. Inter family marriage is not legally prohibited. Still there is a lot of community they are following inter-family marriage and a several cases of genetic disorders reported.