Sayyiduna Atiyyah al-Qurazi (may Allah be pleased with him) said: I was among those who were captured on the day of (Banu) Qurayzah. They would look (for the sign of puberty): whoever had grown pubic hair they would kill, and whoever had not grown it they would leave. I was among those who were left.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14500