It was narrated that Lubabah bint Harith said:
"Husain bin 'Ali urinated in the lap of the Prophet and I said: 'O Messenger of Allah, give me your garment and put on another garment.' He said: 'Water should be sprinkled on the urine of a baby boy, and the urine of a baby girl should be washed away.'" (DE)
English reference (DE): Vol. 1, Book 1, Hadith 522 (DE)
Arabic reference (DE): Book 1, Hadith 564 (DE)