Did Ancient Hindus perfect the science of cloning or were Kauravas products of a technology that modern science has not even (re)developed yet?
(or is it just fiction?)
According to the description in Mahabharata (Adi Parva/Sambhava Parva), the Kauravas were created by splitting the single embryo into 100 parts and growing each part in a separate kund or container.
"Vaisampayana said, 'One day Gandhari entertained with respectful attention the great Dwaipayana who came to her abode, exhausted with hunger and fatigue. Gratified with Gandhari's hospitality, the Rishi gave her the boon she asked for, viz., that she should have a century of sons each equal unto her lord in strength and accomplishments.
Some time after Gandhari conceived and she bore the burden in her womb for two long years without being delivered. And she was greatly afflicted at this. It was then that she heard that Kunti had brought forth a son whose splendour was like unto the morning sun. Impatient of the period of gestation which had prolonged so long, and deprived of reason by grief, she struck her womb with great violence without the knowledge of her husband. And thereupon came out of her womb, after two years' growth, a hard mass of flesh like unto an iron ball.
When she was about to throw it away, Dwaipayana, learning everything by his spiritual powers, promptly came there, and that first of ascetics beholding that ball of flesh, addressed the daughter of Suvala thus, 'What hast thou done?' Gandhari, without endeavouring to disguise her feelings, addressed the Rishi and said, 'Having heard that Kunti had brought forth a son like unto Surya in splendour, I struck in grief at my womb. Thou hadst, O Rishi, granted me the boon that I should have a hundred sons, but here is only a ball of flesh for those hundred sons!' Vyasa then said, 'Daughter of Suvala, it is even so. But my words can never be futile. I have not spoken an untruth even in jest. I need not speak of other occasion.
Let a hundred pots full of clarified butter be brought instantly, and let them be placed at a concealed spot. In the meantime, let cool water be sprinkled over this ball of flesh.' "Vaisampayana continued, 'That ball of flesh then, sprinkled over with water, became, in time, divided into a hundred and one parts, each about the size of the thumb. These were then put into those pots full of clarified butter that had been placed at a concealed spot and were watched with care. The illustrious Vyasa then said unto the daughter of Suvala that she should open the covers of the pots after full two years. And having said this and made these arrangements, the wise Dwaipayana went to the Himavat mountains for devoting himself to asceticism.
"Then in time, king Duryodhana was born from among those pieces of the ball of flesh that had been deposited in those pots. According to the order of birth, king Yudhishthira was the oldest. "