Genetic researchers at the University of Gottingen in Germany have produced 65 mouse fetuses using sperm that was grown from embryonic stem cells. In an interview with Deutschlandfunk, a German radio station, Dr. Wolfgang Engel, director of Human Genetics at the university, said 12 baby mice had been born using the method, but the mortality rate was high.
"We started out with 65 embryos from egg cells which had been inseminated by the sperm-like cells created in our lab. Of those, 12 reached full term and were born. But seven of the newborn animals died within a period ranging from three days to five months after birth of causes which we have not been able to determine," he said.
Engel said he and his team of researchers will now attempt to generate sperm from early germ cells in the testicles; they might also try to use bone marrow. But they cannot run any tests on people, in compliance with German laws that ban all genetic research using human stem cells.
"This is all still in the very early experimental stages," Engel told Deutschlandfunk. "If it works in the mouse, I'm sure it will also work in the human."