Mukhtasar Muslim

Ibn al-Munkadir narrates that he heard from Sayyiduna Jabir (may Allah be pleased with him) who said: The Jews used to say that if a man has intercourse with his wife from behind (but in the vagina), then the child born will be cross-eyed (i.e., sees one thing as two). Upon this, the verse was revealed: "Your wives are a place of sowing of seed for you, so come to your place of cultivation however you wish" (Al-Baqarah: 223). (Meaning: come to the place of cultivation and not to the well, and the place of cultivation is only that where the seed is sown and grows, not the place where the seed is wasted.)