Britain's fertility regulator has approved a scientist's application to edit the genetic code in human embroys. 

In a statement Monday, the Human Fertilisation and Embryology Authority said it has approved research led by scientist Kathy Niakan to try to understand the genes that embryos need to develop successfully.

Niakan, of the Francis Crick Institute, plans to use gene editing to analyze the first week of an embryo's growth.

Paul Nurse, director of the Francis Crick Institute, said Niakan's research would "enhance our understanding of (in vitro fertilization) success rates, by looking at the very earliest stage of human development."

The scientists will not be allowed to implant any embryos used in their research into women. The embryos, which would be donated by couples undergoing IVF treatment who do not need them, must also be destroyed after two weeks.

Last year, Chinese researchers made the first attempt at modifying genes in human embryos. Their laboratory experiment didn't work but raised the prospect of altering genes to repair the genes of future generations.

Scientists say such techniques could lead to treatments for inherited diseases like muscular dystrophy and HIV. Critics warn that tweaking the genetic code this way could eventually lead to genetically modified human babies.

Around the world, laws and guidelines vary widely about what kind of research on embryos that will change the genes of future generations, is allowed. In the U.S., the National Institutes of Health won't fund this kind of research but private funding is allowed.

Critics warn that tweaking the genetic code this way could eventually lead to a slippery slope.

"This is the first step on a path that scientists have carefully mapped out towards the legalization of (genetically modified) babies," said David King, of anti-gene manipulation group Human Genetics Alert, last month when the British fertility regulator held its meeting to decide on granting the gene editing license.

The Associated Press contributed to this report.

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