Sunan ad-Daraqutni 470 — on the ruling of the urine of a boy and girl

A narrator named Qatadah has stated: "This is when they have not eaten anything; if they begin to eat, then the urine of both of them should be washed."

Sayyiduna Abu Samh (may Allah be pleased with him) narrates: I used to serve the Noble Prophet (peace and blessings be upon him). When he wanted to perform ghusl (ritual bath), he would say to me: "Turn your face away." So I would turn my face away and provide a screen. (Once, after he had performed ghusl,) either Imam Hasan (may Allah be pleased with him) or perhaps Imam Husayn (may Allah be pleased with him) was brought to him, and he urinated on the Prophet’s chest. The Noble Prophet (peace and blessings be upon him) called for water and sprinkled it over the area, and said: "If a boy urinates, it should be sprinkled in this way, and if a girl urinates, it should be washed."