Purity: Looking at the Private Parts of a Corpse
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 551:
Looking at the private parts of a corpse is unlawful, except in the case of a husband and wife. If the person giving ghusl looks [at the private parts], he commits a sin but the ghusl does not become invalid.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)