"The messenger of Allah was asked about the 'Aqiqah and he said: "Allah, the mighty and sublime, does not like Al-Uquq' as if he disliked the word (Al-Aqiqah). He said to the Messenger of Allah: 'But one of us may offer a sacrifice when a child is born to him.' He said: 'Whoever wants to offer a sacrifice for his child, let him do so, for a boy; two sheep, Mukafaatan, (of equal age), and for a girl, one.' (One of the narrators) Dawud said: 'I asked Ziad bin Aslam about the word Mukafaatan and he said: 'Two similar sheep that are slaughtered together.
Sunan al-Nasa'i 4140
It was narrated from 'Abdullah bin Buraidah, from his father, that:
أَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ حَدَّثَنَا الْفَضْلُ، عَنِ الْحُسَيْنِ بْنِ وَاقِدٍ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم عَقَّ عَنِ الْحَسَنِ وَالْحُسَيْنِ .
the Messenger of Allah offered the 'Aqiqah for Al-Hasan and Al-Husain.
Sunan al-Nasa'i 4141
It was narrated from Salman bin 'Amir Ad-Dabbi that the Messenger of Allah said:
"I came to the Prophet and asked him about the sacrificial meat. I heard him say: 'For a boy, two sheep, and for a girl, one sheep, and it does not matter if they are male or female."'
Sunan al-Nasa'i 4145
It was narrated from Umma Kurz that the Messenger of Allah said:
"Muhammad bin Sirin said to me: 'Ask Al-Hasan (Al-Basri) from whom he heard this Hadith about the 'Aqiqah.' I asked him about that and he said: 'I heard it from Samurh."'