“My uncle through suckling came and asked permission (to enter) but I refused to admit him until I asked the Messenger of Allah. So the Messenger of Allah said: “Let him in since he is your uncle.’” She said: “It is only the woman who suckled me; I was not suckled by the man.’ So he said: ‘Indeed he is your uncle, so let him in.’”  

جَاءَ عَمِّي مِنَ الرَّضَاعَةِ يَسْتَأْذِنُ عَلَىَّ فَأَبَيْتُ أَنْ آذَنَ لَهُ حَتَّى أَسْتَأْمِرَ رَسُولَ اللَّهِ ﷺ فَقَالَ رَسُولُ اللَّهِ ﷺ فَلْيَلِجْ عَلَيْكِ فَإِنَّهُ عَمُّكِ قَالَتْ إِنَّمَا أَرْضَعَتْنِي الْمَرْأَةُ وَلَمْ يُرْضِعْنِي الرَّجُلُ قَالَ فَإِنَّهُ عَمُّكِ فَلْيَلِجْ عَلَيْكِ  

“No, the semen is the same.”  

عَنْ رَجُلٍ لَهُ جَارِيَتَانِ أَرْضَعَتْ إِحْدَاهُمَا جَارِيَةً وَالأُخْرَى غُلاَمًا أَيَحِلُّ لِلْغُلاَمِ أَنْ يَتَزَوَّجَ بِالْجَارِيَةِ فَقَالَ لاَ اللِّقَاحُ وَاحِدٌ