Cousin couples are marriages between a man and a woman who are related through one of their parents. Though uncommon today, many states still allow first cousins to marry. The rest only require the couple be second cousins, or further apart. | Cousin couples are marriages between a man and a woman who are related through one of their parents. Though uncommon today, many states still allow first cousins to marry. The rest only require the couple be second cousins, or further apart. |