Late last year, a Chinese scientist shocked the world when he announced that he’d secretly orchestrated the birth of two babies whose genomes were modified using the gene-editing tool CRISPR.

Now, a Russian scientist wants to continue his experimentation, even though his moves received worldwide condemnation surrounding the ethics of gene editing, and despite new research showing those babies may be at risk of early death.

Scientists have had about six months to research the potential effects of the edited genes, and the results aren’t exactly encouraging. A team of scientists led by Rasmus Nielsen looked at the records of more than 400,000 people. Researchers found that those with a modified CCR5 gene, the same one edited in the two babies, were 21% less likely to live until 76 years old.

They weren’t able to determine exactly why they were at a greater risk to die early, but suspect it could be because a modified CCR5 gene also makes people more susceptible to West Nile and influenza.

The truth is, we don’t know much about how this all went down, since He Jianku, the Chinese scientist who originally used CRISPR to edit the embryo’s genomes, operated in an alarming amount of secrecy.

In twin girls born last November, as well as a third baby expected this summer, He performed a procedure to edit their DNA, specifically a gene called CCR5, in an effort to make them immune to HIV. (The twins’ father was HIV positive, and did not want to pass it along to his offspring.)

Biologists have long understood that gene editing would likely occur in some form in the future, since the point of our studies into DNA and genomes is to help understand our bodies and how we can prevent and fight disease, as well as avoid passing it on to future generations. But most biologists assumed that day wouldn’t come until many more years of study, debate, peer review and testing to get a better idea of what exactly would happen to the resulting children.

Instead, He Jianku operated in almost total secrecy, with biologists around the world learning only of his experimentation when the babies were born. In a later defense of his actions, which he said he was proud of, he admitted that even his own university didn’t know what he was up to. In the aftermath, several prominent scientists called for a total moratorium on gene editing, as well as the creation of a formal process for how and if to proceed with it in the future.

That’s the big ol’ question. For scientists like He Jianku, gene editing has the potential to be a powerful tool, one that eliminates disease and drastically increases human quality of life.

Sounds too good to be true, right?

It is. We simply don’t have enough knowledge about genes to eliminate ones that lead to disease without unknown, potentially worse consequences. Our knowledge about genetics has grown substantially over the past century, particularly since the 1950s, when we learned about the structure of DNA. But we still have loads to learn about all the ways our genes interact within our bodies and amongst each other, as well as how they mutate when faced with outside interactions like editing.

Plus, gene editing gets into dangerous territory where people’s personal biases can rear their ugly heads.

Bioethicists worry about a future where people who have access and wealth can enter a fertility clinic and produce an embryo with genes they find superior – perhaps making sure their baby has a certain hair or skin color, or a gene that makes them likely to excel as an athlete. That future hasn’t materialized, but it is important to establish an ethical foundation in the world of gene-editing to avoid racism, classism and ableism going forward.

There’s also ethical questions about using gene editing to eliminate diseases that lead to differently abled bodies. In their visions for the future, many able-bodied scientists use language that describe differently abled bodies as bad or undesirable. There are differently abled people who may look forward to scientific advancements that make their lives easier. In the meantime, though, scientists and able-bodied people must be mindful to be accepting of those differently abled bodies, listen to their experiences and work to promote accessibility in their own communities, rather than talk about eliminating them entirely.

Of course, these aren’t reasons to stop studying gene editing and mutation entirely – the field of science would never progress if researchers gave up just because they didn’t know what would happen in a certain experiment. But it is a reason to proceed with extreme caution, with consultation from a variety of scientists worldwide and work to guarantee that an experiment designed to save lives doesn’t lead to fatal consequences.