According to the Technology Review, past efforts by us scientists to use CRISPR have been inconsistent and resulted in "editing errors" that gave weight to arguments the technique "would be an unsafe way to create a person".
A researcher at Oregon Health and Science University has reportedly become the first in the United States to genetically modify a human embryo, according to a report from the MIT Technology Review.
Previous reports of editing human embryos were all by scientists in China.
None of the embryos were allowed to develop for more than a few days, according to sources familiar with the study.
However, the edited embryos were not allowed to develop for more than a few days and were never meant to be implanted in any womb.
Scientists wanted to show that they can eradicate or correct genes that cause inherited disease, like thalassemia. As a result, any genetically modified child would then pass the changes on to subsequent generations via their own germ cells-the egg and sperm.
In theory, the technique could also be used to create "designer" babies with specific desirable qualities, such as eye color or strength, and possibly even greater intelligence, a prospect that has sparked a lively ethical debate in the scientific community and beyond. First reported by MIT Technology Review, the first attempt at editing the genes of human embryos in the U.S. has been carried out by researchers in Portland, Oregon.
Mitalipov's group appears to have overcome earlier difficulties by "getting in early" and injecting CRISPR into the eggs at the same time they were fertilised with sperm.
Mitalipov's results are still "pending publication", he told MIT.
The research, led by Shoukhrat Mitalipov, head of OHSU's Center for Embryonic Cell and Gene Therapy, involves a technology known as CRISPR which allows scientists to modify genes quickly and effectively.
Speaking to Technology Review, a scientist familiar with the project said: 'It is proof of principle that it can work. Until the numbers are published, it will not be clear to what extent this reduced mosaicism.
But in February, a report from the U.S. National Academy of Sciences and the U.S. National Academy of Medicine said that clinical trials for gene editing of human reproductive cells "could be permitted in the future, but only for serious conditions under stringent oversight".