Three generations in one house and ADHD running clean through all of them — that was my neighbor's family. Grandfather never diagnosed, dad figured it out at 40, and the youngest kid spotted at 8. Once the family history clicked, everything made sense backwards and forwards. The hereditary link is genuinely strong, not just coincidence. Is ADHD hereditary if one parent has it breaks down exactly how it passes between generations and what to watch for. Your son having a diagnosed parent actually puts you ahead - most families spend years confused before connecting those dots.