A man being given a kunyah before he has a child
حَدَّثَنَا أَبُو بَكْرٍ، حَدَّثَنَا وَكِيعٌ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ مَوْلًى، لِلزُّبَيْرِ عَنْ عَائِشَةَ، . أَنَّهَا قَالَتْ لِلنَّبِيِّ ـ صلى الله عليه وسلم ـ كُلُّ أَزْوَاجِكَ كَنَّيْتَهُ غَيْرِي . قَالَ " فَأَنْتِ أُمُّ عَبْدِ اللَّهِ " .
It was narrated from Aisha that she said to the Prophet(ﷺ): "All of your wives have a Kunyah except me." He said: "You are Umm Abdullah".