Travis (plaintiff) and Teresa Arneson (defendant) disagreed on who should have custody of their three-year-old daughter Grace. Due to cerebral palsy, Travis uses a wheelchair and has personal attendants who assist with daily life, but he considered himself independent and able to care for his daughter. When Travis filed for divorce, the court entered an interim order requiring weekly alternating custody. Travis’s attendant said he cared for Grace during his weeks. Four months after Travis filed for divorce, a woman moved in with him who provided daycare for Grace and four other children. They later married but were not married when the court determined custody. Teresa did not allow Grace to go to Travis’s for daycare during Teresa’s weeks because Travis would not let Grace go to Teresa’s at night. Meanwhile, court-appointed social worker Judy Zimbelman evaluated both parties and questioned whether Travis could care for Grace by himself. Zimbelman noted that Travis’s physical limitations made him less able to care for Grace than Teresa. Zimbelman also found that Grace needed to be with Teresa on a daily basis because of her emotional ties to her mother and young age. Zimbelman explained that Grace could not understand changing homes weekly, needed stability, and would suffer if she could not see her mother a week at a time. The trial court awarded joint, primary physical custody to Teresa. Travis appealed, arguing that his physical disability and the tender-years doctrine impermissibly influenced the court.