Does looking upon the private parts of a child establish perpetual prohibition?
Chapter on What is Prohibited to Marry and Combining Between Them and Other Matters
Al-Mughni
Book of Marriage
Primary text
Perpetual prohibition is only established through looking or touching when the person has reached an age from which sexual enjoyment can be derived, such as a daughter aged nine years or older. A young child does not incur this ruling.
Supporting text
It is narrated from Ahmad regarding a seven-year-old girl that if one kisses her, her mother becomes prohibited to him. Al-Qadi interprets this as being limited to the age where desire is typically present.