A group of Chinese scientists injected a human being with cells genetically edited using CRISPR-Cas9 technology. This is the first time CRISPR has been used on a fully formed adult human and it’s encouraged a biomedical battle between China and the United States.

The scientists from China are hoping the genetically edited cells will help their patient fend off a virulent type of lung cancer in hopes it might work on other cancer patients who have not responded to chemotherapy, radiation and other treatments.

However, another group of scientists in the U.S. proposed a similar study in June of this year. The $250 million study funded by Sean Parker’s new cancer institute is slated to take place at the University of Pennsylvania. The National Institutes of Health (NIH) has already given the research a thumbs up, but it’s still awaiting approval from the Food and Drug Administration (FDA).

Scientists have already tried to test other gene-editing techniques to treat human diseases. One method taking on HIV proved effective but CRISPR offers a much simpler path to healing by using an enzyme to snip out an unwanted genetic code.

Using CRISPR-Cas9 technology, scientists could take out all the genes ready to grow a genetically inherited cancer in a person before that cancer starts. In theory, they could also wipe out the disease by removing the genes causing the disease after it has already started wreaking havoc on the body. This is what both the Chinese and U.S. scientists hope to discover, but it looks like China already has its foot in the door.

The U.S. has a much more stringent medical regulatory system than many parts of the world and though the trial here is small and only intended for those patients with no other options it still must go through a process before we start altering human genetic code.

The first U.S. trial isn’t meant to see whether or not the treatment is effective, however. Instead, it’s merely to test its safety.

CRISPR isn’t fool-proof. Sometimes the Cas9 technology splices genes at the wrong place and can actually cause cancer.

Meanwhile, Editas Biotechnology has proposed running a CRISPR trial by 2017 for genes causing blindness in humans. Stanford also has plans in the works for a human CRISPR trial to repair genes causing sickle cell anemia.

But China’s early steps should be used as a cautionary tale for this new technology. Another group of Chinese scientists already ran CRISPR experiments on human embryos that didn’t go very well — at least two-thirds of the embryos were found to have genetic mutations and only a fraction of the 28 surviving embryos (out of 86 total tested) contained the replacement genetic material.

So it seems as though China has beat the U.S. to being first, we still have a long way to go in determining whether or not the technology is even safe enough at its current iteration to use for currently incurable diseases.