A UK regulator has approved British scientists’ request to use a controversial technique called CRISPR to edit genes in human embryos. The method involves precisely locating and removing parts of the genetic code, in order to replace them with other segments of DNA. It's the first time a federal authority has approved a gene-editing technique such as this for research in embryos.

The UK's Human Fertilization and Embryo Authority gave the go-ahead on Monday to a group of researchers, led by biologist Kathy Niakan, at the Francis Crick Institute. Niakan and her team have no intention of implanting the embryos into the womb, so none will ever become a person. They want to use the CRISPR method to edit out genes in embryos that might hamper healthy development. The idea is to get a better understanding of which genes are essential for an embryo to grow normally. The research could help improve how embryos develop after being conceived through in vitro fertilization (IVF), the Institute claims.

The researchers will only study the embryos during the first seven days following conception; that's when the fertilized egg grows from one cell to around 250 cells in size. The embryos, which will all donated from patients undergoing IVF treatments, are not allowed to survive past 14 days, according to Time.

The study could get started in the next couple of months, as soon as the researchers gain additional approval from a UK ethics board. If they do, it won't be the first time that human embryo genomes have been edited with the CRISPR technique. Scientists in China used the method on a group of embryos to try to remove a gene known to cause a fatal blood disorder. China has guidelines that govern how gene-editing is done, but the research does not require the same kind of federal approval as the UK and US.

CRISPR has been both heralded as a revolutionary medical technique and condemned as a gateway for so-called "designer babies." If used properly, such gene editing could be used to remove DNA responsible for life-threatening diseases; it could also theoretically be used to enhance a person's intelligence or beauty. Because of the unknowns associated with CRISPR, a group of international experts called for a ban on using the technique on embryos that might result in a human person. The experts said it would be "irresponsible" to introduce edited DNA into the human gene pool, when we still know very little about the potential health risks involved.