What does the Bible say about marrying cousins? Can first cousins marry? I am also interested in the relationship of third or fourth cousins. If two children of first cousins marry, is this relationship considered third or fourth cousins?
The Bible does not forbid marriage between cousins. However, marriage between first cousins is illegal in about half the states in the U.S.; the Biblical principle here is that God has instituted the government’s authority, so there may be a legal issue depending on where you live. But it’s not a sin biblically.
The children of one’s first cousin are actually “first cousins, once removed.” The children of first cousins are second cousins to each other. Here’s a helpful page to keep all that straight, an essay and chart called “What Is a First Cousin, Twice Removed?”: https://wehavekids.com/family-relationships/What-Is-a-Second-Cousin-Twice-Removed-Chart-Explains-All
Hope this helps!