Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada., answers: “The knowledge of this thing is based on reports that we have received from the traditions and narrations. As we can determine from the sources, the laws of marriage prevailing in those days were different from the laws we have now. They are told from reports that Hawwa’ (Eve) used to deliver one boy and a girl in one birth, another boy and a girl in another birth, and then the boy from the first birth was allowed to marry the girl from the second birth.
However, it is no more valid for us as the Qur’an has declared them as taboo. Please refer to verse no. 23 in Surat An-Nisa’ to know about the categories of women forbidden in marriage.
We should not venture to speculate on matters that are not known to us or matters as regards which we have no sources to rely upon. The Qur’an forbids us from indulging in useless speculations on such matters. We should save our time for more beneficial issues of practical nature. The Prophet, peace and blessings be upon him, is reported to have said: “Of the excellence of one’s faith is that he or she should leave alone that which does not concern him or her.”
Sheikh Hamed Al-Ali, instructor of Islamic Heritage at the Faculty of Education, Kuwait and Imam of Dahiat As-Sabahiyya Mosque, adds: “Scholars said that Eve used to get pregnant with twin boy and girl, and then get pregnant with another twin boy and girl. The boy from the first birth would marry the girl from the second one, and the boy from the second birth would marry the girl from the first one. This how they grew and the population started, until Allah, the Almighty, forbade the marriage between Mahrams (unmarriageable relatives mentioned in Surat An-Nisa’ (4), verse no. 23) for a reason known only to Allah, the Almighty.”