I have a 15yrear old son. His father has always been in and out of jail his whole life. His father won't work because he doesn't want to pay child support. My son needs health insurance and he won't provide that either. My husband wants to adopt him because he has been his only father he's had and wants to provide for the things that his dead beat dad won't not that he hasn't already but my son needs medical insurance. I've tried to contact him but all I have is phone number and his moms address. I have no idea where he lives and he won't tell me! What should I do next?

Adoption laws vary by state, especially in regards to those done without the consent of an absent parent. In general the biological parent must be found and must give permission to the court. It is extremely risky to proceed without that, although many states do have conditions for doing so. There are stories of a bio parent 'winning' a child back from adopting parents, especially sad if the child is very young.
You really need a lawyer to handle this. You can inquire at your Family Court about the process where you live.
Keep in mind that adoption is a slow process and your son won't be able to be on your health plan past 18 unless he's in college.

First, have you talked to your husband's medical insurance carrier? I don't know believe there is a block on claiming a step child as a dependent, especially if the child can be claimed a dependent on a tax return. So adoption might not be necessary to get him covered.

However, as Joy said, there is no legal impediment to applying for adoption. If the father refuses to work for fear of child support, he should welcome the adoption since it will free him of the support obligation. With his consent, the adoption will be easy, but you still need a local attorney to prepare the paper work.

And under the new health care laws, your son can be covered until 26 I think.

I would take the deadbeat to Family Court and get an Order for support/insurance.
Then use that to negotiate the adoption.