Contrary to widely held beliefs and longstanding taboos in America, first cousins can have children together without a great risk of birth defects or genetic disease, scientists are reporting today. They say there is no biological reason to discourage cousins from marrying.

Are first cousins inbreeding?

First cousins have an inbreeding coefficient of 0.0625. But the estimate that 0.2 percent of U.S. marriages are between people who are second cousins or closer needs to be treated with plenty of caution.

What happens if you have a baby with your cousin?

First cousins are somewhat more likely than unrelated parents to have a child with a serious birth defect, mental retardation or genetic disease, but their increased risk is nowhere near as large as most people think, the scientists said.