Untold numbers of mouse "disease models" are still made this way in nearly every university lab in the world.
Richard Palmiter, a molecular biologist at the University of Washington who collaborated with Brinster, recalled the electricity of their weekly telephone conversations to discuss the work on transgenic mice. He described himself as the tactician and Brinster as the long-term strategist.
"Ralph would say, 'Here's the big picture: How are we going to solve this problem?' " Palmiter said. "We had this just wonderful collaboration."
Brinster's work on egg cells also helped pave the way for other advances in biology that are now commonplace, such as in vitro fertilization, cloning, and the creation of "knockout" lab animals, which are missing a particular gene.
He received perhaps the most publicity for a curious experiment in 1982, in which he transferred genes for rat growth hormone into mice, producing mice that grew to twice their normal size.
In an interview, Brinster was modest about his accomplishments.
"I got lucky," Brinster said. "I always tell my students, 'If you can choose between talent and luck, take luck.' "
He said he became interested in biology while growing up on a farm in Cedar Grove, in North Jersey. His family raised goats to provide milk for children who were allergic to cow's milk, and he became keenly aware of the importance of good breeding to a farmer's livelihood.
"A 5 to 10 percent change in efficiency can make or break a farm business," he said.
Brinster studied animal science at Rutgers University, then served in the Air Force during the Korean War before getting his veterinary degree and his doctorate at Penn.
Most recently, Brinster has worked on the stem cells that give rise to sperm. Years ago, his lab developed a technique for transferring sperm stem cells from one animal to another. This could prove useful for male cancer patients who become infertile during therapy, as the cells could be harvested beforehand.
He is working with scientists at Children's Hospital of Philadelphia on this concept. They have frozen sperm stem-cell samples from child cancer patients in hope that the cells can be cultured and multiplied for later use.
Brinster lives in Gladwyne with his wife, Elaine. They have four children, one a trial lawyer and three who have followed him into the medical profession: two surgeons and a veterinary pathologist.
Among the other medal recipients are scientists in such fields as probability theory, energy efficiency, and rocket propulsion. Brinster is the lone veterinarian - not just this year but in the 50-year history of the national medals.
Contact staff writer Tom Avril at 215-854-2430 or firstname.lastname@example.org.