"Revolutionary" gene editing technology is controversial because it presents the possibility of creating genetically modified humans, but it also has the potential to make a positive difference to human health, bioethicist Dr. Sarah Chan of the University of Edinburgh said.
A team of researchers at Oregon Health and Science University in Portland have become the first in the US to create genetically modified human embryos.
Since 2015, scientists in China have published three reports on the gene editing of human embryos, which caused an ethical storm and led to calls for an international moratorium on human genome editing amid fears they could be used to produce a baby.
However, the team led by biologist Shoukhrat Mitalipov, head of the Center for Embryonic Cell and Gene Therapy at Oregon Health and Science University, has gone even further than the Chinese researchers in editing the human genome, MIT Technology Review reported.
Researchers in both countries used the gene-editing technique CRISPR to change the DNA of a number of one-cell embryos.
The scientists at Portland reportedly surpassed their Chinese colleagues because they edited the genomes of many more embryos and corrected defective genes that cause inherited diseases.
One of the ethical concerns about the gene editing of embryos is that they could potentially be implanted into a women's uterus.
Dr. Sarah Chan, deputy director of the Mason Institute for Medicine, Life Sciences and Law at the University of Edinburgh, the fact that the embryos were destroyed is "very important."
"One of the concerns that is sometimes raised about gene editing in human embryos, is that one day it may be used to create genetically modified human beings.
Now, various reports that have come out looking at the ethics of this issue have said that actually there are potentially useful applications of gene editing to prevent human inherited disease, but we are not at the point yet where we are confident to apply the technology to do that."
"So, while we are still investigating the scientific issues, while we are still trying to better understand the safety issues involved, I think it's very important that we make a distinction between research that is done in the laboratory and remains in the laboratory, versus any attempt to implant edited embryos which would be attempting to create genetically modified humans," Chan said.
While gene editing techniques such as CRISPR have the potential to cure inherited diseases in the future, scientists are still limited to trying to understand the diseases, before they can genetically edit a cure.
In fact, the possibility of modifying DNA has been available for decades via the use of recombinant DNA technology, which allows the joining together of DNA molecules from different species.
However, CRISPR is "revolutionary" because it provides a more efficient and precise way of targeting genes, making it less costly and time-consuming.
"We are now at the point where we are able to use gene-editing technology in many contexts at a lower cost, to do things better and more precisely.
The reason that some people also say that makes it controversial is because it brings us closer to one day being able to use gene-editing technologies for human therapeutic applications, to use gene-editing technologies to cure disease."
"I suppose people say that's controversial because we would be interfering with the genome of humanity, but in my view anything that improves human health and welfare and makes people's lives better is a good step."