Hadith.896 - Imam Ali عليه السلام used to say:
"There is no issue if a boy calls the adhan (call to prayer) before reaching the age of puberty, and there is no issue if the mu'adhdhin (caller to prayer) is in a state of janabah (major ritual impurity), but he should not perform the iqamah (second call to prayer) until he has performed ghusl (ritual purification)."