For decades, scientists around the world have followed the “14-day rule,” which stipulates that they should let human embryos develop in the lab for only up to two weeks after fertilization. The rule — which some countries (though not the United States) have codified into law — was meant to allow researchers to conduct inquiries into the early days of embryonic development, but not without limits. And for years, researchers didn’t push that boundary, not just for legal and ethical reasons, but for technical ones as well: They couldn’t keep the embryos growing in lab dishes that long.
More recently, however, scientists have refined their cell-culture techniques, finding ways to sustain embryos up to that deadline. Those advances — along with other leaps in the world of stem cell research, with scientists now transmogrifying cells into blobs that resemble early embryos or injecting human cells into animals — have complicated ethical debates about how far biomedical research should go in its quest for knowledge and potential treatments.
Now, in the latest updates to its guidelines, the International Society for Stem Cell Research has revised its view on studies that would take human embryos beyond 14 days, moving such experiments from the “absolutely not” category to a “maybe” — but only if lots of conditions are first met.
“We’ve relaxed the guidelines in that respect, we haven’t abandoned them,” developmental biologist Robin Lovell-Badge of the Francis Crick Institute, who chaired the society’s guidelines task force, said at a press briefing.
The change is not expected to unleash a torrent of such research. In some countries, including Australia and the United Kingdom, it would require a change in law….
Scientists say that studying human embryos a bit longer could let them peer into the “black box” of days 14 to 28 of development, a time when different cell types emerge, the body’s tissues tilt toward specialization, and the placenta begins to take shape. It could help researchers understand what goes wrong in miscarriages or what causes congenital abnormalities. It could also validate whether the models scientists use to mimic human embryonic development, such as animal embryos, are legitimate stand-ins, and, if not, in what ways they’re lacking. (Past 28 days is when women typically find out they’re pregnant, so researchers can obtain tissue from abortions and miscarriages beyond this point to study those phases of development….)
The current guidelines carry particular weight in the United States, in part because Congress, through a 25-year-old policy tied to the Health and Human Services Department’s funding, has prohibited federal dollars from going to effectively all research using human embryos. But that also means that health agencies like the National Institutes of Health can’t impose policies on any such research that it would otherwise fund….
The above comes from a May 26 story in StatNews.