It was narrated from ‘Ali bin Abi Talib (رضي الله عنه) that The Messenger of Allah (ﷺ) said concerning the nursing infant:
`Sprinkle water on the urine of a boy and wash the urine of a girl` Qatadah said: This is so long as they are not eating solid food; if they are eating solid food, both are to be washed.