Any person under age 18 and/or not yet graduated from high school must have a conservator. Biological parents are a child’s conservator by legal definition; no court order is required to assign conservatorship in this case. Biological parents have co-equal rights and duties regarding their child—until they separate or divorce. In this case, the court assigns custody—legally known in Texas as conservatorship—to one or to both parents in some degree.
Conservatorship also applies to the adoption of a child. Once the adoption has taken place, the parent-child relationship is the same as a biological relationship.