In the United States, second cousins are legally allowed to marry in every state. However, marriage between first cousins is legal in only about half of the American states. All in all, marrying your cousin or half-sibling will largely depend on the laws where you live and personal and/or cultural beliefs.
Is it worse to marry your first or second cousin?
Ultimately, marrying your first cousin carries some risk. But the odds of healthy offspring dramatically improve with each new distance of relation. Second cousins share only 6.25 percent of their genes and third cousins share just over 3 percent.
What state can you marry your second cousin?
According to the NCSL, cousin marriage is legal in: Alabama, Alaska, California, Colorado, Connecticut, District of Columbia, Florida, Georgia, Hawaii, Maryland, Massachusetts, New Jersey, New Mexico, New York, North Carolina (in North Carolina, first-cousin marriage is legal, but double-cousin marriage is prohibited),
Instead of the usual 12.5% of DNA that first cousins share, the two of you share around 25% of your DNA. This is the same amount that you would share with a grandparent, a half sibling or an aunt or uncle. Lets get into a discussion of why the two of you share 25% of your DNA.