The man whose research led to the world's first test-tube baby more than three decades ago, has died at age 87.
Robert Edwards, who later won the Nobel Prize, began experimenting with in vitro fertilization, or IVF, in the late 1960s. His work, controversial at the time, eventually led to the birth of the world's first "test tube baby," Louise Brown, on July 25, 1978.
Since then, IVF has resulted in about 5 million babies worldwide, according to the European Society for Human Reproduction and Embryology.
In 2010, Edwards was awarded the Nobel Prize in Physiology or Medicine and was knighted the following year.
Brown, now 34, told the BBC that she had "always regarded Robert Edwards as like a grandfather."
The work he pioneered along with surgeon Patrick Steptoe, "has brought happiness and joy to millions of people all over the world by enabling them to have children," Brown said. Steptoe died in 1988.
The Associated Press quoted the University of Cambridge, where Edwards was a professor, as saying he passed away peacefully in his sleep at his home just outside Cambridge.
IVF, which joins a human egg and sperm in the laboratory before transferring the resulting embryo back into the womb, sparked enormous controversy after the birth of Brown was announced to the world. Brown's mother had been unable to conceive naturally due to complications from a blockage in her fallopian tubes.
Dr. Peter Braude, emeritus professor of obstetrics and gynecology at Kings College London, who was at Cambridge when Edwards and Steptoe were developing IVF, called Edwards "an extraordinary scientist."
"There was such hysteria around the kind of work he was doing," Braude told The Associated Press. He said Edwards had halted his research for two years as he sought "to work out what the right thing to do was, whether he should continue or whether he was out on a limb."
"I think people now understand that [Edwards] only had the best motivation," he told the AP. "There are few biologists that have done something so practical and made a huge difference for the entire world."