The DNA test has been used by many people across the US. (Representational Pic)
DNA test is generally used to determine the ancestry. But in the US, it has revealed a disturbing trend: That incest is far more common in the country than many think. Widespread genetic testing has uncovered many cases of children born to close biological relatives, providing an unprecedented accounting of incest in the society. A research published in a psychiatry text book in 1975 put the rate of children born of incest at one in a million. But recent studies have shown the number has reached one in 7,000.
CNN spoke to Victoria Hill, who discovered the disturbing truth through a DNA test.
The 39-year-old started talking about her family tree with an ex-boyfriend at their high school reunion after she had taken a DNA test.
Both were surprised to learn that their family make-up was similar, so the man also decided to take the same test. Ms Hill then received a text message confirming her worst fear - she was his sister. And her father was not her biological father.
"I was traumatised by this. Now I'm looking at pictures of people thinking, well, if he could be my sibling, anybody could be my sibling," she told CNN.
She later got to know that she had many more siblings that just the brother she grew up with - 22.
"I have slept with my half-sibling. I went to elementary school with another," said Ms Hill.
CNN highlighted her case to uncover something called an accidental incest, which proliferated due to lack of regulations.
These cases emerged because some people donated their sperm to help women conceive. The story that really put fertility fraud on the national radar was that of Dr Donald Cline, who fathered at least 90 children in Indiana.
Babies born as a result of incest are at an increased risk of having birth defects and genetic disorders. These identities are confirmed by third party tests that look for homozygosity, or ROH for short, which reveals chunks of identical genetic material in the DNA.