Dr. Muhammad ʿAli al-Bar writes: “Given what we now know from embryology, we hold such a scenario to be impossible: the ovum is fertilized by one—and only one—sperm cell, and once fertilization occurs it cannot be fertilized a second time through another act of intercourse. This is likewise the conclusion reached by the jurists al-Shafiʿi and Ibn al-Qayyim, may Allah have mercy on them.”

… End of the Book of Judicial Rulings