Causal parentage has been a central justification for child support law and for expanding parental rights to couples who conceive with donor gametes, including lesbian couples. Like many famous philosophers, courts insist adults incur parental duties when their voluntary acts create a child who needs care. This causation of peril principle, which is familiar to tort law, does generate personal duties. Unlike a stranger with only a general duty of beneficence, someone who helps create an infant has a special duty to ensure the infant receives care. However, this duty is too weak to ground parenthood. If other willing caregivers are available, casual parents are not obligated to raise the child personally. Nor do they have a right to do so. Someone who creates a perilous situation (a causal parent) cannot object if someone else rescues their victim (the child). Nevertheless, causal parentage may ground limited child support from a political perspective. Many theories of distributive justice are sensitive to causal responsibility. A community may conclude causal parents have a political duty to help meet a child’s needs. Unfortunately, in its haste to privatize child-rearing, American child support law compounds rather than facilitates distributive justice.