A Chinese scientist’s claim to have created the first genetically edited babies has evoked widespread condemnation from the scientific community, for good reason. Playing with humanity’s genetic code could open a Pandora’s box. Scientists could eventually be able to alter DNA to create genetically enhanced human beings, which goes against all the ethics and norms of life as we know it.

The Chinese scientist, He Jiankui, used a gene-editing technique known as CRISPR to alter the DNA of two unborn children to make them resistant to HIV.

Regardless of the fact that the little data He has revealed suggests that his efforts might or might not have worked, and in fact may have put the babies’ health at risk, there’s a huge difference between gene therapy and genetic engineering. The therapy can help eliminate diseases but in genetic engineering, scientists alter the entire genetic structure of the resulting human being — changes that are then passed on to future generations. Obviously it would have profound societal implications if we began to create perfect children in labs. Parents would start asking for and scientists would start making the kinds of babies that have no imperfections – even though there is no such thing as a perfect human. These made-to-order babies could be endowed with greater abilities, to look better, to be more intelligent, more talented. These privileges would also be enjoyed by their offspring.

In opening the door to this kind of modification, we are likely opening the door to all kinds of questions. What kind of traits would be selected or not selected? How would gene editing be regulated from country to country? And because this is a process that only the wealthy could afford, then only they would benefit. The less wealthy would not have the ability to make these super babies, shooting down the belief we have always held that all people are created equally.

Using CRISPR to edit a gene can have unintended, negative consequences on health. Editing one part of DNA to treat one health problem could result in another problem. For example, it’s possible to accidentally disrupt a system that protects from cancer but can make people more susceptible to dying from the flu.

Finally, there’s the argument that modifying genomes is inherently dangerous because there could be hidden longer-term health and safety consequences. We don’t know all the ways it will affect the individual.

The project that the scientist He has claimed to have produced the world’s first gene-edited babies has thankfully been stopped by the Chinese government, which is declaring his work as being both unlawful and unethical. Not only that but He’s so-called achievement was greeted with almost universal condemnation, with most mainstream scientists and ethicists complaining that He violated established scientific and ethics standards, among other complaints. He is being accused of unduly experimenting on humans with an unproven and potentially unsafe technology. For his part, He has defended himself and even claimed that a second pregnancy with a gene-edited baby was underway.

The debate about gene editing is not a new one. The prospect of creating genetically modified humans was openly debated in the late 1990s. But it has now regained attention and with it the re-emergence of controversy.

Any kind of gene editing, even for medical purposes, would start the world on a slippery slope to using it for non-therapeutic and enhancement purposes. Genetic research holds the promise to prevent, cure and even eliminate disease. But when it is used to create designer babies, then a moral and ethical line has been crossed from which there is no return. Taken to its extreme, gene editing could create classes of individuals defined not by who they are but how they were made.