John D. Gearhart, 77, of Swarthmore, a renowned developmental geneticist, professor, and stem cell research pioneer, died Wednesday, May 27, at home of gastric cancer.

Beginning in 1964, when he graduated from Pennsylvania State University with a degree in biological science, Dr. Gearhart studied the role of stem cells and genetics in plants, animals, and humans, and held prestigious positions at, among other places, the University of Maryland, Johns Hopkins University, and the University of Pennsylvania.

He worked at the Institute for Cancer Research in Philadelphia in the 1970s, and was an associate professor of anatomy at the University of Maryland School of Medicine and associate professor of pediatrics, cell biology and anatomy, and gynecology and obstetrics at Hopkins.

Dr. Gearhart is best known for leading a research team at Hopkins that first identified and isolated human embryonic stem cells.

At Penn, beginning in 2008, Dr. Gearhart served in many roles, including as first director of the Institute for Regenerative Medicine. His family said he was an active faculty member until his death.

“Former colleagues and students remember him for the excitement and conviction he brought to the research lab, classroom and beyond,” the family wrote in a tribute.

After spending time as a child roaming the fields and orchards in the Allegheny Mountains, where he was born, Dr. Gearhart had a lifelong appreciation of nature, flowers in particular. Long after he had become immersed in his studies of genetics and stem cell activity in flowers, insects, animals and humans, he loved to traverse his garden and contemplate the flora.

His daughter, Sarah Vater, recalled walking with him as he pointed out his favorites. His professional expertise was in lilacs.

Born in Homer City, Pa., Dr. Gearhart moved to Philadelphia when he was 6 with one of his two brothers after their father died. He became a ward of the state and attended Girard College, then an all-male school for orphans. After Penn State, he earned a master of science degree from the University of New Hampshire in 1966 and a Ph.D. in genetics, development and embryology from Cornell University in 1970.

Dr. Gearhart studied genetics in relation to Down syndrome and congenital birth defects for years. But he is known most for his work in 1998 at Hopkins, where he and other scientists identified and then isolated human pluripotent stem cells from human primordial germ cells. That led to important advances in drug development, transplant therapy, tissue growth, and ethical standards in human embryonic stem cell research.

Dr. Gearhart speaks at the wedding of his daughter, Sarah, as his other daughter, Elizabeth, looks on. He doted on the women.
COURTESY OF THE GEARHART FAMILY
Dr. Gearhart speaks at the wedding of his daughter, Sarah, as his other daughter, Elizabeth, looks on. He doted on the women.

As his work broadened to include the ethics and public policy of stem cell science, Dr. Gearhart received many awards, including the 1999 Gold Plate Award from the Academy of Achievement and the Basil O’Connor Starter Research Award from the March of Dimes Birth Defects Foundation.

He also visited Capitol Hill more than 100 times as an adviser to politicians and officials on scientific research and wrote more than 200 papers in his field. “John’s foremost concern was that scientists would learn to communicate their discoveries in a way that avoided alienation and misrepresentation," the family wrote.

At home, with daughters Sarah and Elizabeth Fisher, Dr. Gearhart shared his love of reading by advising the girls which of his books likely suited them best. “He read everything he could, from science to the human condition,” Sarah said.

Dr. Gearhart dances with daughter Sarah at her wedding. They used to stroll in the garden and talk about flowers.
Courtesy of the Gearhart family
Dr. Gearhart dances with daughter Sarah at her wedding. They used to stroll in the garden and talk about flowers.

Dr. Gearhart was also an avid cook, although not wedded to specific recipes. He would stock up on the essentials at the market, his daughter said, and then create his own dishes. His specialty was fresh fish, and he had a true love of crab cakes.

Most of all, Dr. Gearhart doted on his daughters. He was always checking with them to make sure they took time to relax and have fun.

“He was in love with me and my sister. We were the center of his universe,” daughter Sarah said.

In addition to his daughters, Dr. Gearhart is survived by former wives Patricia Gearhart and Shannon Fisher, from both of whom he was divorced, and two brothers.

Private services are to be later.