The Prophet ﷺ said, "The urine of a baby girl is to be washed, while the urine of a baby boy is to be sprinkled with water."
أخبرنا مجاهد بن موسى قال حدثنا عبد الرحمن بن مهدي قال حدثنا يحيى بن الوليد قال حدثني محل بن خليفة قال
قال النبي ﷺ يغسل من بول الجارية ويرش من بول الغلام
[Its chain of transmission is sahih] Abu Dawud narrated it in the Book of Purification, chapter on urine of a child that touches the garment, hadith no. 376, and Ibn Majah in the Book of Purification, chapter on what has been said about the urine of a child who has not yet eaten food, hadith no. 526, from Mujahid bin Musa with this same chain. It is also found in Sunan al-Kubra, hadith no. 293, and Ibn Khuzayma graded it sahih, hadith no. 283, as did Hakim and Dhahabi.