-snip- > They have blood tests though, before marriage, so maybe it > is just dependent on the results. -snip- There's an old saying, "Don't believe everything you think." No DNA analysis existed when those blood tests were introduced.  The blood tests weren't designed or legislated to prevent consanguinity.  To be blunt, they were intended to detect sexually transmitted disease, although some states added additional tests for other conditions over time.  DNA testing and comparisons are relatively recent and I know of no state that routinely performs them prior to marriage.     Lou