More information is needed to answer this question. If your son is still under 18 and he was in your custody when you or your husband became citizens he may have automatically become a U.S. citizen. Contact and immigration attorney to help you file for his U.S. passport and certificate of citizenship.
Gabriela M. Lopez, Esq.
If your son is currently a minor (under 18) and was in your custody when you naturalized he may have already become a citizen automatically. You should consult with an immigration attorney who can figure out if this was the case.