How can I get my 4 year old severly autistic son's diapers covered?

JocelynAnn, I'm sorry about your situation.  I think the answer will depend on your insurance company.  You should understand your insurance company's appeals process, which may include time limits for them to make a decision on a claim either way.  If they deny the claim, you can appeal, and again after a set period of time, if there is not resolution, you may be able to submit a complaint to your state health insurance commissioner.  I am not an insurance lawyer, and don't know where you're located, but you can also consult with an insurance advocate where you're located (generally a lawyer or someone familiar with insurance company practices).  The other possibility is you can create a health savings account ("HSA") to save money pre-tax for health expenses.  You may need to show the HSA administrator your son's diagnosis and the developmental issues he is facing to get these costs covered.  There is NOTHING harder than trying to help a child with a developmental disorder like autism do things with their body that other parents (almost) take for granted.  Hang in there, I hope things get better.  BTW, do you have a behavioral therapist to help with potty training?

Thank you so much for thinking of me and answering my much needed question.
First of alll, I don't know if this will make a difference but I live in NJ, which has the highest rate of autism in the country!
Second, I have heard about this flex-spending account where you put some money away tax free, you purchase the item, and then (she said, she is deaf) that they send you a check for the amount in which your purchased your item...?   If this is correct, I have no problem setting this up for my child.  Does anyone know if what I am saying is true for the state of NJ?

Thanks so much for your concern!  My Joshua thanks you!