A person, licensed child-placing agency, or the Department of Family and Protective Services designated managing conservator of a child in an irrevocable or unrevoked affidavit of relinquishment has a right to possession of the child superior to the right of the person executing the affidavit, the right to consent to medical, surgical, dental, and psychological treatment of the child, and the rights and duties given by Chapter 153 to a possessory conservator until such time as these rights and duties are modified or terminated by court order.
Tex. Fam. Code § 161.104