New study results suggest that ADHD could be hereditary. Although there is no known cause of ADHD, one theory involves the impact of endo-disrupting chemicals or EDCs, which have the power to alter DNA. In a study published in JAMA Pediatrics, a group of older women who received a powerful (and now banned) EDC during pregnancy now are more likely than the general population to have a grandchild with ADHD. Although more study is needed, the results hint that ADHD may be an epigenetic disorder.