Robert Edwards, a feisty British embryologist who fundamentally transformed human procreation, received the 2010 Nobel Prize in medicine Monday for the development of clinical in vitro fertilization.

'By a brilliantcombination of basic and appliedmedicalresearch, [Dr.] Edwards overcame one technical hurdle after another in his persistence to discover a method that would help to alleviate infertility,' the Nobel Prize committee said in its award citation Monday. 'His contributions represent a milestone in the development of modern medicine.'

Dr. Edwards, 85 years old, is in failing health and was too ill to make any public response to the award, his colleagues said. 'He understood this morning that he was finally awarded the prize and he was smiling plenty when his wife, Ruth, gave him the news,' said embryologist Jacques Cohen, the senior editor of Reproductive Biomedicine Online, which Dr. Edwards founded.

His discoveries about human embryos have so far enabled the birth of four million children to couples world-wide. The ability to create human embryos in the laboratory also is essential for genetic screening of human embryos and human embryonic-stem-cell research. Ultimately, it may pave the way for the genetic alteration of human embryos, several embryologists and biomedical ethicists said.

'His achievements go way beyond IVF,' said embryologist Alan Handyside at the Bridge Centre clinic in London, who pioneered the genetic diagnosis of human embryos.

Working in close collaboration with gynecologist Patrick Steptoe, who died in 1988, Dr. Edwards overcame entrenched political and religious hostility, as well as the stern disapproval of many other scientists at the time, to pioneer the basic techniques of human embryology that led to the birth of the first test-tube baby, Louise Brown, in England on July 25, 1978.

'It took them 10 years and over 100 attempts,' Dr. Cohen said. 'It demonstrates tremendous tenacity.'