Is it OK for cousins to marry?
Scientifically speaking, procreating with your cousin isn't that risky. In much of the world, consanguineous marriage between cousins is very common. For most Americans, however, marriage between cousins is at best a punchline, at worst a taboo. In many states, it is illegal for first cousins to get married.
Is it a sin to marry your cousin?
The laws of many countries regarding prohibited relationships do not necessarily follow the biblical prohibitions nor those of any particular church. The Bible does not, for example, forbid cousins from marrying, but it does prohibit sexual relations with several other close relatives.
Is it OK to marry your 2nd cousin?
In the United States, second cousins are legally allowed to marry in every state. What's more, the genetic risk associated with second cousins having children is almost as small as it would be between two unrelated individuals. Marriage between first cousins, however, is legal in only about half of American states.