Does cleaning a child's urine and diapers nullify ablution?

The Wudu' (ablution) is not invalidated by cleaning a child's urine and diaper, because touching impurities does not nullify Wudu'. Rather, it is obligatory to wash off impurities when intending to pray. It is stated in "Fatawa of the Permanent Committee for Issuing Fatwas": "Wudu' is not nullified by washing off impurities from the body of the person performing Wudu' or anyone else." Ibn Baz mentioned that touching sanitary tools, bathroom tiles, or a child's clothes wet with urine does not nullify Wudu', but whatever has been touched by impurity must be washed. Ibn Uthaymeen said that a woman is not required to perform Wudu' if she washes her child and touches his private parts; rather, she should only wash her hands, due to the absence of lust.