Sunnah.com reference : Book 8, Hadith 160English translation : Book 8, Hadith 1113Arabic reference : Book 8, Hadith 1102
Narrated Abu Hurairah (RA):
A man said, "O Allah's Messenger, my wife has given birth to a black son." He asked, "Have you any camels?" He replied, "Yes." He asked, "What is their color?" He replied, "They are red." He asked, "Is there a dusky (dark) one among them?" He replied, "Yes." He asked, "How has that come about?" He replied, "It is perhaps a strain to which it has reverted (i.e. heredity)." He said, "It is perhaps a strain to which this son of yours has reverted."

[Agreed upon].
وَعَنْ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- { أَنَّ رَجُلًا قَالَ: يَا رَسُولَ اَللَّهِ! إِنَّ اِمْرَأَتِي وَلَدَتْ غُلَامًا أَسْوَدَ? قَالَ: "هَلْ لَكَ مِنْ إِبِلٍ?" قَالَ: نَعَمْ.‏ قَالَ: "فَمَا أَلْوَانُهَا?" قَالَ: حُمْرٌ.‏ قَالَ: "هَلْ فِيهَا مَنْ أَوْرَقَ?", قَالَ: نَعَمْ.‏ قَالَ: "فَأَنَّى ذَلِكَ?", قَالَ: لَعَلَّهُ نَزَعَهُ عِرْقٌ.‏ قَالَ: "فَلَعَلَّ اِبْنَكَ هَذَا نَزَعَهُ عِرْقٌ".‏ }  مُتَّفَقٌ عَلَيْهِ .‏  1‏‏1 ‏- صحيح.‏ رواه البخاري (5305)‏، ومسلم (1500)‏.‏