The Messenger of Allah ﷺ said: Two sheep which resemble each other are to be sacrificed for a boy and one for a girl. Abu Dawud said: This is a sound tradition, and the tradition narrated by Sufyan is misunderstanding. (Using translation from Abū Dāʾūd 2836)
قَالَ رَسُولُ اللَّهِ ﷺ «عَنِ الْغُلَامِ شَاتَانِ مِثْلَانِ وَعَنِ الْجَارِيَةِ شَاةٌ»