The scientist considered by many as the chief architect of stem cell research has been given a knighthood in the New Year Honours list.
Professor Evans is credited with discovering embryonic stem cells
Martin Evans is professor of mammalian genetics at Cardiff University and a Fellow of the Royal Society.
In the 1980s, he discovered embryonic stem cells, which form all tissues in the body of a mouse and can be removed and grown separately in the laboratory.
He also helped create a method to alter genes in mice with amazing accuracy.
News of the honour has come as the perfect birthday gift to the scientist, who was born on 1 January 1941 at Stroud in Gloucestershire, UK.
"I'm delighted, it has come completely out of the blue," Professor Evans told BBC News Online.
This breakthrough, known as gene targeting, is assisting the drive to develop new treatments for human illnesses.
Another of his firsts was using gene therapy to cure cystic fibrosis in "gene knockout" mice.
"[Gene therapy] has had its ups and downs, but it's one of the ways forward for medical science," Professor Evans said.
After graduating from the University of Cambridge in 1963, Professor Evans gained his PhD at University College, London.
In 1978, he returned to the University of Cambridge and it was here that he discovered embryonic stem cells in mice with his collaborator Dr Matthew Kaufman in 1981.
Dr Gail Martin, of the University of California at San Francisco, who was working independently in the same area, is credited with coining the name for the cells.
In 1999, Professor Evans left Cambridge to join Cardiff University where he is now director of the School of Biosciences.
Embryonic stem cells in humans have also subsequently been isolated and cultured in the laboratory - but it remains one of the most controversial areas of scientific study.
George Bush's administration has blocked the public funding of this type of research in the US because of his party's ethical reservations about embryo research.
Stem cells are the "master cells" in the embryo that give rise to all cell types - such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.
Scientists think they could be able to use stem cells to replace those specialised cells that are lost or damaged in patients with disease.
Professor Evans becomes one of the Knights Bachelor for his services to medical science.