Bukayr reported that he saw 'Abdullah ibn Ja'far kissing Zaynab, the daughter of 'Umar ibn Abi Salama when she was about two years old.  

أَنَّهُ رَأَى عَبْدَ اللهِ بْنَ جَعْفَرٍ يُقَبِّلُ زَيْنَبَ بِنْتَ عُمَرَ بْنِ أَبِي سَلَمَةَ وَهِيَ ابْنَةُ سَنَتَيْنِ أَوْ نَحْوَهُ  

Al-Hasan said, "If you avoid looking at the hair of anyone in your family except your wife or a little girl, then do so."  

أَنْ لاَ تَنْظُرَ إِلَى شَعْرِ أَحَدٍ مِنْ أَهْلِكَ إِلاَّ أَنْ يَكُونَ أَهْلَكَ أَوْ صَبِيَّةً فَافْعَلْ