Developmental biologist Fredrik Lanner of the Karolinska Institutet in Stockholm recently publicized his successful editing of human DNA in embryos. Despite previous attempts to edit genes in human embryos, Lanner is the first to yield viable human embryos after gene editing and announce it to the public.

Lanner was able to accomplish this landmark achievement using the powerful gene-editing tool, CRISPR/Cas9. Originally discovered in bacteria, CRISPR/Cas9 was identified as the prokaryotic, acquired immune system to confer resistance to viral DNA.

Upon further study into its specificity and potential as a DNA repair system, researchers at the Broad Institute of MIT and Harvard harnessed the CRISPR-Cas9 system to demonstrate its efficiency in eukaryotic cells.

Historically, genome editing in eukaryotic cells has been a challenge with obstacles such as circumventing the nucleus and dealing with greater numbers of sets of chromosomes, commonly regarded as ploidy. CRISPR/Cas9 has resolved many of the issues of eukaryotic gene editing with its ability to target multiple genomic loci specifically and drive homology-directed repair.

Lanner’s impetus to conduct such an experiment was motivated by his desire to answer some of the unresolved questions concerning the development of early embryos.

Doing so, the Swedish researcher hopes to invite translational researchers to apply his work to “devise new infertility treatments, prevent miscarriages and learn more about stem cells,” according to his report.

Understanding the early development of cells may also facilitate disease prevention and amelioration in adults with diseases such as diabetes and Parkinson’s.

Although Lanner’s research exists as a testament to the power of CRISPR/Cas9 and the progress geneticists are making, his study reignites many of the ethical debates initially sparked by previous attempts to edit human genes in viable embryos. That is, Lanner’s research invites scientists as well as the public to assess the morality and legality of editing the human genome.

Multiple arguments have been proposed both for and against humane genome editing. Supporters celebrate the ability to do so as a therapy to prevent embryos with a genetic predisposition to life-threatening or seriously debilitating diseases.

However, those in opposition argue that inviting scientists to edit the human genome will allow the manufacturing of “designer babies”: or made-to-order children with traits specified by parents or scientists.

This debate continues to boil with the advent of other novel technologies. For example, prenatal genetic screenings to detect conditions for Down syndrome have invited parents to choose whether or not to carry the pregnancy to term knowing their child may be born with the disease.

Research into editing the human genome has only accelerated and magnified the complexity of this debate as improvements in the efficiency of the gene-editing technology continue.

Lanner is not the first scientist to stoke the fire of this debate, nor will he be the last with the continued interest in devising methods to prevent early-developing diseases.

During this time, the public remains responsible for being informed about the science and understanding its social implications, argues Lanner. One day, they will be responsible for deciding the fate of this technology at a tool for human disease prevention.