It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said regarding an infant boy: "Sprinkling water over the urine of a boy is sufficient, and if a girl's urine gets on something, it should be washed." Qatadah says that this ruling is until they start eating and drinking, and when they start eating and drinking, then whatever their urine touches must be washed in both cases.