When a man has intercourse with his wife through the vagina but being on her back. the child will have squint, so the verse came down:" Your wives are your tilth; go then unto your tilth as you may desire" (ii. 223)
سَمِعَ جَابرًا يَقُولُ كَانَتِ الْيَهُودُ تَقُولُ إِذَا أَتَى الرَّجُلُ امْرَأَتَهُ مِنْ دُبُرِهَا فِي قُبُلِهَا كَانَ الْوَلَدُ أَحْوَلَ فَنَزَلَتْ { نِسَاؤُكُمْ حَرْثٌ لَكُمْ فَأْتُوا حَرْثَكُمْ أَنَّى شِئْتُمْ}