No special conditions.
One generation apart, half the shared DNA of first cousins.
Allowed in California and every other US state.
Neighboring states.
Cousin marriage laws change at the state line. Here's how California's neighbors handle first cousins.
| State | First cousins | Details |
|---|---|---|
| Oregon | Banned | |
| Nevada | Banned | Also a criminal offense. |
| Arizona | Legal with conditions | Only if both are 65 or older, or one of you can't have children. |
See all 50 states on the cousin marriage map. Laws change, so confirm with your county clerk before you plan anything.
Legal is one question. Genetics is another.
Children of first cousins have roughly a 5 to 6% chance of a serious birth defect, compared with about 3% for unrelated parents. For second cousins, the extra risk is under one percentage point.
The risk comes from recessive conditions. Cousins are more likely to carry the same hidden variant from a shared grandparent. A carrier screen tells you whether you two actually do. If you don't, most of the extra risk goes away.
Not sure exactly how you're related? The cousin calculator names any relationship, and a DNA comparison settles it for good.
Cousins? Check your carriers.
The single most useful test a related couple can take before kids. One couple result, with a genetic counselor included.
California cousin questions.
Can you marry your first cousin in California?
Yes. California allows first cousins to marry with no special conditions, and has for well over a century.
Can you marry your second cousin in California?
Yes. Second cousins can legally marry in California, as in every US state.
Can you marry your first cousin once removed in California?
Yes. If first cousins can marry in California, so can first cousins once removed.
Is it legal to date your cousin in California?
Dating isn't regulated, but marriage and incest laws can apply to close relatives. In California, first cousins can legally marry. Second cousins and beyond are fine.