Research shows, that 1st cousin marriages are actually very common all over the world, but only recently in United states, it's usually frowned upon since there is a slight chance of offspring birth defects. Although some people argue that birth defects more importantly involve a women's age, some states (USA) have already laws that prohibit marriages between first cousins.
Famous people who married their cousins include:
Franklin D. Roosevelt
So if you were in love with your cousin, with you consider marriage?