Sahih Muslim 2181
Sahih Muslim · Book 39: The Book of Greetings · Forbidding A Hermaphrodite From Entering Upon Non-Mahram Women
'A'isha reported that a eunuch used to come to the wives of Allah's Apostle (ﷺ) and they did not And anything objectionable in his visit considering him to be a male without any sexual desire. Allah's Apostle (ﷺ) one day came as he was sitting with some of his wives and he was busy in describing the bodily characteristics of a lady and saying:
وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ ، عَنْ مَعْمَرٍ ، عَنِ الزُّهْرِيِّ ، عَنْ عُرْوَةَ ، عَنْ عَائِشَةَ ، قَالَتْ كَانَ يَدْخُلُ عَلَى أَزْوَاجِ النَّبِيِّ صلى الله عليه وسلم مُخَنَّثٌ فَكَانُوا يَعُدُّونَهُ مِنْ غَيْرِ أُولِي الإِرْبَةِ - قَالَ - فَدَخَلَ النَّبِيُّ صلى الله عليه وسلم يَوْمًا وَهُوَ عِنْدَ بَعْضِ نِسَائِهِ وَهُوَ يَنْعَتُ امْرَأَةً قَالَ إِذَا أَقْبَلَتْ أَقْبَلَتْ بِأَرْبَعٍ وَإِذَا أَدْبَرَتْ أَدْبَرَتْ بِثَمَانٍ . فَقَالَ النَّبِيُّ صلى الله عليه وسلم " أَلاَ أَرَى هَذَا يَعْرِفُ مَا هَا هُنَا لاَ يَدْخُلَنَّ عَلَيْكُنَّ " . قَالَتْ فَحَجَبُوهُ .
As the comes in front tour folds appear on her front side and as she turns her back eight folds appear on the back side. Thereupon Allah's Apostle (ﷺ) said: I me that he knows these things; do not, therefore. allow him to cater. She (" A'isha) said: Then they began to observe veil from him.