وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ أُمِّ الْمُؤْمِنِينَ، أَنَّهَا قَالَتْ جَاءَ عَمِّي مِنَ الرَّضَاعَةِ يَسْتَأْذِنُ عَلَىَّ فَأَبَيْتُ أَنْ آذَنَ لَهُ عَلَىَّ حَتَّى أَسْأَلَ رَسُولَ اللَّهِ صلى الله عليه وسلم عَنْ ذَلِكَ فَجَاءَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَسَأَلْتُهُ عَنْ ذَلِكَ فَقَالَ ‏"‏ إِنَّهُ عَمُّكِ فَأْذَنِي لَهُ ‏"‏ ‏.‏ قَالَتْ فَقُلْتُ يَا رَسُولَ اللَّهِ إِنَّمَا أَرْضَعَتْنِي الْمَرْأَةُ وَلَمْ يُرْضِعْنِي الرَّجُلُ ‏.‏ فَقَالَ ‏"‏ إِنَّهُ عَمُّكِ فَلْيَلِجْ عَلَيْكِ ‏"‏ ‏.‏ قَالَتْ عَائِشَةُ وَذَلِكَ بَعْدَ مَا ضُرِبَ عَلَيْنَا الْحِجَابُ ‏.‏ وَقَالَتْ عَائِشَةُ يَحْرُمُ مِنَ الرَّضَاعَةِ مَا يَحْرُمُ مِنَ الْوِلاَدَةِ ‏.‏

Yahya related to me from Malik from Hisham ibn Urwa from hisfather that A'isha, umm al-muminin said, "My paternal uncle bysuckling came to me and I refused to give him permission to enteruntil I had asked the Messenger of Allah, may Allah bless him andgrant him peace, about it. The Messenger of Allah, may Allah bless himand grant him peace, came and I asked him about it. He said, 'He isyour paternal uncle, so give him permission.' So I said, 'Messenger ofAllah! The woman nursed me not the man.' He said, 'He is your paternaluncle, so let him enter.' " A'isha said, "That was after theveil had been imposed on us." A'isha added, "What is haram bybirth is made haram by suckling." Translation Not Available

Book reference: Muwatta Imam Malik Book 30 Hadith 1276
Web reference: Muwatta Imam Malik Book 30 Hadith 2