Navigating a Change of Primary Care Physician for Your Child

Question
This is an ethical question more than a medical question.  I'm grasping at straws as to what to do, so I hope you either have some advice or can direct me to a good source for advice.  We have been taking our 22 month old son to a Family Practice physician since he was born.  This physician works in our family practice where both my husband and I have our doctors.  We have been there every 3-5 months since our son was born. They have been really good to us and have gotten to know our family well.  Recently we had a bit of a scare when our son started limping severely.  My husband and I together made two visits to the office to have him looked at.  We ask a lot of questions and try to be as informed as possible (via web or talking to friends) about possible causes and treatments of problems before we make a doctor visit.  A week after our last visit, my son's doctor called my husband and informed him that they do not want us back in their practice and we need to find other doctors.  The only explanation he would give was that my husband "offended someone in their practice" and that "they need to keep their staff so we have to go."  They also said "you have too many questions that we can't answer, so you would probably be happier elsewhere."  Since then I have tried to contact this doctor and he will not return my calls.  I was with my husband the entire time we were in the office and did not witness him doing or saying anything that I would consider "offensive."  My questions to you are: does the practice have any legal or ethical obligation, based on physician training, to give us an explanation, and offer to support us in getting set up elsewhere?  Do I have any recourse?  Is there some kind of family practice certifying body or other organization that I could complain to about their treatment of us.  We've been dumped without explanation, at a time when my son needs care.  Any suggestions?  

Answer
Does the practice have any legal or ethical obligation, based on physician training, to give us an explanation, and offer to support us in getting set up elsewhere? Yes, they are required in most states to provide care for at least 30 days til you get a new doctor.

Do I have any recourse? Yes, you can call the state medical board and report them.

Is there some kind of family practice certifying body or other organization that I could complain to about their treatment of us. Yes, the American Academy of Family Physicians and the local and state chapter of same.

We've been dumped without explanation, at a time when my son needs care. Any suggestions?
However, I would not want these kind of doctors taking care of my family. OK?