Of note, an excerpt on a related blog (excerpted from a paywalled article: http://www.sciencemag.org/content/347/6228/1301.full http://www.sciencemag.org/conten

Of note, an excerpt on a related blog (excerpted from a paywalled article: http://www.sciencemag.org/content/347/6228/1301.full http://www.sciencemag.org/content/347/6228/1301.full) ... Rumors are rife, presumably from anonymous peer reviewers, that scientists in China have already used CRISPR on human embryos and have submitted papers on their results. They have apparently not tried to establish any pregnancies, but the rumors alarm researchers who fear that such papers, published before broad discussions of the risks and benefits of genome editing, could trigger a public backlash that would block legitimate uses of the technology. ... But scientists don't yet understand all the possible side effects of tinkering with germ cells or embryos. Monkeys have been born from CRISPR-edited embryos, but at least half of the 10 pregnancies in the monkey experiments ended in miscarriage. In the monkeys that were born, not all cells carried the desired changes, so attempts to eliminate a disease gene might not work. The editing can also damage off-target sites in the genome. Those uncertainties, together with existing regulations, are sufficient to prevent responsible scientists from attempting any genetically altered babies, says George Church, a molecular geneticist at Harvard Medical School in Boston. Although he signed the Science commentary, he says the discussion “strikes me as a bit exaggerated.” He maintains that a de facto moratorium is in place for all technologies until they're proven safe. “The challenge is to show that the benefits are greater than the risks.” ... Although many European countries ban germline genetic engineering in humans, the United States and China do not have such laws. Research with private funds is subject to little oversight in the United States, although any attempts to establish a pregnancy would need approval from the U.S. Food and Drug Administration. In China, any clinical use is prohibited by the Ministry of Health guidelines, but not by law.