The age of “designer babies” may be fast approaching.

On April 18, 2015, Chinese scientists published their reports on the gene editing of human embryos using clustered regularly interspaced short palindromic repeats (CRISPR) in the online journal Protein and Cell. Their study ignited an ethical debate among scientists across the globe.

While other technologies require engineered proteins that bind to DNA fragments, the newest gene editing tool, CRISPR/Cas9, utilizes RNA-DNA base pairing. The CRISPR technology uses guide RNAs to target the Cas9 nuclease to the desired DNA loci within the genome.

Guide RNAs contain matching sequences that correspond with the DNA to be modified. Nucleases cleave DNA at certain sites, creating double-stranded breaks that can be repaired to generate custom insertions, deletions and substitutions.

Researchers from the Howard Hughes Medical Institute, Behnon Farbound and Barbara J. Meyer, state that the CRISPR/Cas9 system has expanded the world of genome editing because it is simpler and more efficient than other gene-editing techniques.

Junjiu Huang and his research team published the first report of the CRISPR/Cas9 technique on human preimplantation embryos.

According to David Cyranoski, Asian-Pacific correspondent for Nature, an international journal of weekly science, they utilized the CRISPR/Cas9 gene-editing technique in their efforts to modify a gene responsible for β-thalassaemia, a potentially fatal blood disorder resulting from insufficient hemoglobin production.

Huang and his researchers attempted to avoid ethical objections by using tripronuclear zygotes from local fertility clinics, which had been classified as “non-viable” embryos.

However, Huang’s team faced difficulties in their research. Out of 54 genetically tested embryos, only 28 were successfully spliced, and a select few of these contained the substituted gene.

The team also discovered unintended mutations, assumed to be the result of the CRISPR/Cas9 system operating at other sites of the genome.

While some may argue human embryo gene editing is the answer to eliminating genetic diseases, there are many risks associated with tampering with the human genome.

As seen with Huang’s research, there is a risk that cuts will be made at other places in the genome. Genetic mosaics may result if the nuclease does not cut both copies or if cell division begins before the corrections are finished.

According to Edward Lanphier, the president and chief executive officer of Sangoma Biosciences, the exact effects of genetically modified embryos would not be seen until after birth, and even then, it might take years for problems to reveal themselves.

Even now, scientists don’t fully understand the human genome and the function of every DNA sequence. This makes large-scale modifications potentially disastrous.

Because germ line modifications are heritable, human embryo gene editing could alter future generations. Researchers are also concerned that genetic modification of human embryos could be a slippery slope toward misuse of the CRISPR/Cas9 system.

This technology has the potential to create “designer babies,” allowing parents to modify genes for gender, hair color and eye color, as well as other characteristics.

Lanphier reasons that the use of CRISPR/Cas9 technology in human embryos does not offer therapeutic benefits over established, available methods.

The United States has not banned germ line modification, but it is highly discouraged. The US National Institutes of Health’s Recombinant DNA Advisory Committee has voiced that it will not approve proposals for genetically engineered human embryos at this time.

This research is in the early stages of development, but that doesn’t mean it won’t be ready in the near future. The question is, are we prepared for when it is?

Surely, the debate will continue to stir up discussion as more researchers attempt to improve Huang’s research. However, scientists must step back and ask themselves if human embryo gene editing has a place in modern medicine.

They must also accept that this technology is fast approaching. Conversations among researchers and bioethicists are needed to shape and formulate viewpoints regarding this challenging and controversial issue.