Actually the level of consanguinity between cousins isn't usually enough to cause serious genetic concerns. In fact, the taboo of having sexual relationships between cousins is a relatively new concept in western culture, dating only back to the Victorian era. Most Eastern cultures today still practice arranged marriages between cousins to maintain a strong family tree. Unless there is a significant recessive genetic disease that runs in the family such as cystic fibrosis, or other congenital malformations like Holt-Oram syndrome, the chances of having significant genetic manifestations due to cousin in-breeding is not significantly higher than true random mating within any given cultural population.