Tenn. Code § 34-6-303
The instrument providing for the power of attorney shall be executed by both parents, if both parents are living and have legal custody of the minor child and shall state with specificity the details of the hardship preventing the parent from caring for the child. If only one (1) parent has legal custody of the minor child, then such parent shall execute the instrument. The other parent must consent in writing to the appointment in the instrument or the executing parent shall explain in the instrument why the consent cannot be obtained. If both parents do not execute the affidavit, then the executing parent shall send by certified mail, return receipt requested, to the other parent at the last known address, a copy of the instrument and a notice of § 34-6-305.
T.C.A. § 34-6-303