You have to be more specific on types of problems they are creating etc. Are they just coaching their kid, or are they being negligent and unfair to other kids, stacking teams, do they know how to coach the game, running interference, etc.
There is nothing wrong with a coach coaching his own boy-we have a rule in our league that only every other coach on staff can have a kid on the team-most have a kid in the org but do not coach his team. I move up one level with them and then stay there until they are out-meaning when they are 7th/8th grade I coach the level below them. I want them to understand the game and learn it from me, I wouldnt trust half of my org with my kids-why? because the majority of youth coaches have very little football knowledge. One of them plays QB-(our backup)-but it would be foolish for me to start him over our older and better starter-there is no issue if they try to be fair.
Where this becomes an issue-is when a kid leapfrogs another solely because of their father-before I came there was a huge problem with this-leading to the rule change-and even then we still have some daddy balling. Fortunately, only about a quarter of them are halfway competent coaches, and they usually wind up quitting/going somewhere else-the team loses, the kid is picked on and the coach is scorned. We have had a huge problem with meddling parents in our organization. One such team in our org last year had almost mutiny because the coach quit midseason and he had 4 assistants, and 4 parents tried to "coach" -I think they won one game. Long and short, theres nothing you can do if you are a parent-minus take your kid off the team. If you are a coach, get rid of them, cut them off at the knees before the season starts with a parent coach meeting.
Oh, and one tip I have learned in the past-I always make sure I know what opposing coaches have kids on the team, and if I scout them (which I only do a handful of times a year) I make note of what position they play. Meaning that if they are a liability out there, we are going to make sure they are exposed.