DNA tests reveal shocking family secrets, including cousin marriage.

The popularity of at-home DNA testing kits has led to many Americans discovering shocking family secrets, including a man who found out he had 30 siblings and a woman who realized she had married her cousin. The availability of cheap and accurate tests from major providers like 23andMe and AncestryDNA has driven the trend, but a recent documentary has also highlighted the damaging health consequences of incestuous families. Experts predict that DNA testing will soon become mandatory at birth and a standard part of medical records.