A year before Zheng Mengzhu was born, her mother, a schoolteacher in Northwest China's Gansu province, and her father, a crop farmer, came to Peking University No 3 Hospital. The couple had long failed in their attempts to bear a child.

But they heard on radio that the Beijing facility had set up a special laboratory where "baby-making" trials were ongoing.

Helmed by the gynecologist Zhang Lizhu, who is now a 95-year-old retiree, the Test-Tube Baby Lab as the unit was called in the 1980s, was mixing human eggs and sperms in petri dishes to create embryos, which would be transplanted into the wombs of women seeking to get pregnant through such assistance.