I have actually heard it is a lot higher chance than that if both of you have it. Four out of five of us have it in our family. Can you imagine! My husband is a saint. He is the only one without it and keeps us all on track. My advice if you haven't done this already is read, read, read as much as you can about it. It will not only help your child out, but it will help you improve your life. I would actually read bits and pieces to my husband so he learned a great deal too. There is actually a book called "Mom's with ADHD". It is awesome. Your life becomes very hectic w kids whether they have ADD or not. Also, check into CHADD. It's the nationwide support group for ADD. Every major city has one. My group has been amazingly helpful. There are people who have ADD, spouses of people w ADD, and parents w kids who have ADD attending. Good luck and remember there are LOTS of pluses to having ADHD!
im not a doctor but there is a 1 in 5 chance they may have adhd or add.