All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions. If the father touches the urine of his son who is old enough to eat food, he has to wash what was affected by this urine, but if the son does not yet eat food (is still suckling) then it is enough to splash some water over all the place of the urine without pouring too much water. However, his excrement should be washed. As regards the urine or excrement of a girl, they must be washed whether she has started eating food or is still suckling but in both cases, this does not invalidate one’s ablution who touches or is affected by the urine of the child; whether a male or female, his ablution is not invalidated even by touching the penis of the child. Khaleel said about the things which invalidate ablution: 'Touching the private parts with a desire.' This means that 'the touching that invalidates ablution is when the person touching gets some sexual pleasure or seeks it.' This is different from the touching without pleasure or desire; for instance, touching the private parts of a small girl whom one would not usually desire. Therefore, if the father touches the urine or the private parts of their son or daughter, this does not invalidate his ablution. Allaah knows best.