Yet, we wonder where our children picked up their bad habit and how we can help them get rid of it. I assumed my kids would outgrow their bad habits, but my ten-year-old daughter kept biting her nails until two months ago. I showed her pictures of me when I had the same bad habit, and she commented on how ugly my fingers were.Then she decided to try to stop. I bought her some gel polish which kept the nails hard and difficult to bite. She’s now on her way to a set of pretty nails and is so proud.