When child custody, visitation, or support is contested in a divorce or other legal proceeding, courts may appoint a guardian ad litem (often an attorney with experience in family law matters) to investigate and make independent, objective recommendations to the court of what is in the best interest of the child. The guardian ad litem will typically interview the child, the parents, and other people who have contact with the child, and may subpoena witnesses to testify at court hearings, examine and cross-examine witnesses at hearings. The guardian ad litem may also testify regarding her investigation of the circumstances, conclusions, and recommendations to the court.

In New Mexico, when child custody, visitation, or support is contested in a divorce or other legal proceeding, the court has the authority to appoint a guardian ad litem (GAL). This individual is often an attorney with experience in family law matters. The role of the GAL is to serve as an independent investigator and advocate for the child's best interests. The GAL will conduct interviews with the child, parents, and others in the child's life, and has the power to subpoena witnesses for court hearings. Additionally, the GAL can examine and cross-examine witnesses during these hearings. After completing their investigation, the GAL is expected to provide testimony to the court detailing their findings, conclusions, and recommendations regarding the child's welfare. The court then considers the GAL's recommendations when making decisions about custody, visitation, or support.