NEW YORK With rumors that scientists are about to announce they have modified the genes of human eggs, sperm, or embryos, five prominent researchers on Thursday called on biologists to halt such experiments due to fears about safety and eugenics.

The call for a self-imposed research moratorium, which is extremely rare in science, was based on concerns that the work crosses an ethical line, said Edward Lanphier, president and chief executive officer of California-based Sangamo BioSciences Inc., senior author of the commentary published in the science journal Nature.

Humans are not rats or other (experimental) organisms, and this is not something we want to do, Lanphier said in an interview. The research should stop.

Rumors that one or more labs are on the verge of genetically-engineering a human embryo have swirled for months, he said.

Critics of the work say the experiments could be used to try to alter the genetic quality of humans, a practice and belief known as eugenics.

At least two technologies, one called CRISPR and the other known as zinc-finger nucleases, can genetically modify a human embryo. They act as what an article last week in the MIT magazine Technology Review, cited by the Nature authors, called a kind of search-and-replace tool to alter DNA, even down to the level of a single letter.

Experiments have been planned or are underway using the technology on human eggs or embryos, Technology Review reported, to correct genetic defects such as those causing cystic fibrosis or in the BRCA1 breast-cancer gene.

But existing and developing methods can allow parents who carry identified genetic illnesses to keep their children from inheriting them, the Nature authors argued, and genome-editing can itself introduce DNA errors, meaning that the precise effects of genetic modification to an embryo may be impossible to know until after birth. Even then, potential problems may not surface for years.

In theory, genes associated with intelligence, appearance and other nonmedical traits could also be edited into or out of embryos, eggs or sperm.

Genome-editing is being developed to treat HIV/AIDS, some forms of cancer, and other illnesses by altering genes in, say, adults white blood cells. Sangamo is conducting clinical trials of genome editing as a cure for HIV/AIDS that will allow patients to stop taking antiretroviral drugs.

Original post:

Scientists want DNA-changing tests on human embryos, eggs stopped