Sahih Muslim Book - 3, Hadith - 710

حَدَّثَنَا عَبَّاسُ بْنُ الْوَلِيدِ حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ حَدَّثَنَا سَعِيدٌ عَنْ قَتَادَةَ أَنَّ أَنَسَ بْنَ مَالِكٍ حَدَّثَهُمْ أَنَّ أُمَّ سُلَيْمٍ حَدَّثَتْ أَنَّهَا سَأَلَتْ نَبِيَّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنْ الْمَرْأَةِ تَرَى فِي مَنَامِهَا مَا يَرَى الرَّجُلُ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا رَأَتْ ذَلِكِ الْمَرْأَةُ فَلْتَغْتَسِلْ فَقَالَتْ أُمُّ سُلَيْمٍ وَاسْتَحْيَيْتُ مِنْ ذَلِكَ قَالَتْ وَهَلْ يَكُونُ هَذَا؟ فَقَالَ نَبِيُّ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَعَمْ، فَمِنْ أَيْنَ يَكُونُ الشَّبَهُ؟ إِنَّ مَاءَ الرَّجُلِ غَلِيظٌ أَبْيَضُ وَمَاءَ الْمَرْأَةِ رَقِيقٌ أَصْفَرُ فَمِنْ أَيِّهِمَا عَلَا أَوْ سَبَقَ يَكُونُ مِنْهُ الشَّبَهُ.

It was narrated from Qatadah that Anas bin Malik told them that Umm Sulaim narrated, that she asked the Prophet of Allah (s.a.w) about a woman who sees in her dreams what a man sees. The Messenger of Allah (s.a.w) said: "If a woman sees that, let her perform Ghusl." Umm Salamah said: "I felt shy because of that, and I said: 'Does that really happen?"; The Prophet of Allah (s.a.w) said: "How else does resemblance (of the child to either parent) happen? The water of the man is thick and white, and the water of the woman is thin and yellow. Whichever of them prevails, or comes first, the resemblance will be (to that parent)."