NEW YORK, March 22 — As biological research races forward, ethical quandaries are piling up. In a report published yesterday in the journal eLife, researchers at Harvard Medical School said it was time to ponder a startling new prospect: synthetic embryos.
In recent years, scientists have moved beyond in vitro fertilisation. They are starting to assemble stem cells that can organise themselves into embryolike structures.
Soon, experts predict, they will learn how to engineer these cells into new kinds of tissues and organs. Eventually, they may take on features of a mature human being.
In the report, John D. Aach and his colleagues explored the ethics of creating what they call “synthetic human entities with embryolike features” — SHEEFS, for short. For now, the most advanced SHEEFS are very simple assemblies of cells.
But in the future, they may develop into far more complex forms, the researchers said, such as a beating human heart connected to a rudimentary brain, all created from stem cells. Such a SHEEF might reveal important clues about how nerves control heartbeats. Scientists might be able to use other SHEEFS to test out drugs for diseases such as cancer or diabetes.
Whatever else, it is sure to unnerve most of us.
Established guidelines for human embryo research are useless for deciding which SHEEFS will be acceptable and which not, Aach argued. Before scientists get too deeply into making SHEEFS, some rules must be put in place.
Aach and his colleagues urged that certain features be kept off limits: Scientists, for example, should never create a SHEEF that feels pain.
“We’re going to have to get a lot of input from a lot of quarters,” Aach said in an interview. “The problems are just too big.”
But Aach and his colleagues argued that rules based on the time since fertilisation were useless for embryos that were not formed by fertilisation.
Even if ethicists do manage to agree on certain limits, Paul S. Knoepfler, a stem cell biologist at the University of California, Davis, wondered how easy it would be for scientists to know if they had crossed them.
“It gets pretty tricky out there,” Knoepfler said. “They’ve opened the door to a lot of tough questions.” — The New York Times
