Al-Kāfi
Hadith 187عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ النَّوْفَلِيِّ عَنِ السَّكُونِيِّ عَنْ أَبِي عَبْدِ اللَّهِ عَنْ أَبِيهِ ( عليه السلام ) قَالَ الْغُلَامُ لَا يُلْقِحُ حَتَّى يَتَفَلَّكَ ثَدْيَاهُ وَ تَسْطَعَ رِيحُ إِبْطَيْهِ .
3. Ali ibn Ibrahim has narrated from his father from al-Nawfaliy from al-Sakuniy who has said the following: “Abu ‘Abd Allah (a.s.), has narrated from his father (a.s.), who has said, that a boy cannot impregnate until his breast becomes round and the smell of his armpit rises strong.’”