Genome editing is a group of technologies that enables scientists to edit an organism's DNA. One genetic editing technology is called CRISPR-Cas9, which was developed based on a naturally occurring genome editing system in bacteria. CRISPR-Cas9 uses a cell's own machinery to edit the genetic material; scientists can add or remove genetic sequences from an organism's genome. CRISPR-Cas9 can customize an organism's DNA by replacing an existing segment with a customized sequence of DNA.

In 2018, a Chinese scientist announced that he had created the world's first genome-edited babies, twin girls born in November 2018. The scientist wanted to create children who were resistant to Human Immunodeficiency Virus (HIV). The Chinese scientist used CRISPR-Cas9 to disable a gene called CCR5, which encodes a protein that enables HIV to infect cells. This announcement caused outrage in the international scientific community. While genomic editing of bacteria and viruses is commonly used in science, genetic editing of humans remains highly controversial.

Why do you think the news of this new use of CRISPR-Cas9 in humans generated so much anger in the research community and in the world at large? What are the dangers of genomic editing in humans?

A sample answer will include:

The dangers of genetic editing of humans are immense, because simply not enough is known about the CRISPR-Cas9 technology. Genetic editing of humans can cause serious developmental problems and can even be fatal, because a gene that is known to have a specific function may have other undiscovered roles as well. Therefore, removing a gene known to cause a certain disorder, for example, may actually adversely affect the person in some ways. Furthermore, while it is commonplace for scientists to perform genomic editing in bacteria, viruses, plants, and even laboratory animals, the ethics of performing such experiments on humans are highly controversial. Research ethics guidelines prohibit such studies because of the immense risks involved.