Modifies provisions relating to child custody arrangements

SB 638 modifies Missouri's child custody laws to establish a rebuttable presumption that equal or nearly equal parenting time is in a child's best interest. The bill defines key terms like "joint physical custody" and requires courts to consider specific factors - including the child's relationship with both parents, domestic violence history, and the ability of parents to cooperate - when determining custody. It also prohibits awarding custody or unsupervised visitation to parents convicted of certain child-related offenses (e.g., abuse, neglect, or sexual offenses under Missouri law). These changes aim to prioritize frequent, meaningful contact with both parents while protecting children from harm.