Answer
(Fatwa: 739/596/B=1431)
This is the hadith of Bukhari and Muslim, which the author of Mishkat has quoted in his book:
عن جابر قال كانت اليهود تقول إذا إتى الرجل امرأته من دبرها فى قبلها كان الولد أحول فنزلت: نِسَآؤُكُمْ حَرْثٌ لَّكُمْ فَأْتُواْ حَرْثَكُمْ أَنَّى شِئْتُمْ متفق عليه . مشكوة ص:275 ، كتاب النكاح باب المباشرة .
Hadhrat Jabir (رضى الله عنه) reported that the Jews used to say: When a man has intercourse with his wife from rear but through the vagina, the child will have squint, so the verse was revealed: “Your wives are your tilth; go then unto your tilth as you may desire”. (2:223)
Both the methods are correct i.e. either having intercourse through the vagina from backside or from the front side. The saying of Jews is not correct.
To get married in near relatives is not preferred, it is another hadith. You intermixed both of them in each other.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband