Sayyiduna Atiyyah al-Qurazi (may Allah be pleased with him) said: I was also among Banu Qurayzah. Whoever had grown pubic hair was killed, and whoever had not was left alone. At that time I had not grown any hair.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18019