It is foretold in the Twelfth Canto of the Bhagavatam that in this age of Kali married life will be accepted on the consideration of sex only; when the boy and girl are pleased in sex, they get married, and when there is deficiency in sex, they separate. That is not actual marriage, but a combination of men and women like cats and dogs. Therefore, the children produced in the modern age are not exactly human beings. Human beings must be twice-born. A child is first born of a good father and mother, and then he is born again of the spiritual master and the Vedas. The first mother and father bring about his birth into the world; then the spiritual master and the Vedas become his second father and mother. According to the Vedic system of marriage for producing children, every man and woman was enlightened in spiritual knowledge, and at the time of their combination to produce a child, everything was scrutinizingly and scientifically done.
>>> Ref. VedaBase => SB 3.24.15