Gene editing, a revolutionary scientific advancement, allows for precise modifications to an organism’s DNA. This technology holds immense promise for treating genetic diseases and advancing biological understanding. However, its application, particularly in human embryos, has introduced complex ethical considerations. The case of the “Chinese CRISPR babies” brought these discussions to the forefront of global attention, highlighting both the potential and the profound controversies surrounding such interventions.
The Birth of Gene-Edited Twins
In November 2018, the global scientific community was stunned by Chinese scientist He Jiankui’s announcement. Speaking at the Second International Summit on Human Genome Editing in Hong Kong, He claimed that twin girls, Lulu and Nana, had been born with their genes edited to confer HIV resistance. This revelation sparked widespread shock and disbelief among researchers and ethicists. The twins were born in October 2018.
A second woman was also in early pregnancy with another gene-edited embryo, and a third child, Amy, was born in 2019. The experiment, conducted in secret, involved seven couples where the father was HIV-positive and the mother was HIV-negative. News of the gene-edited babies leaked just days before He’s public presentation, prompting him to release a series of YouTube videos to explain his work.
Understanding the CRISPR Intervention
CRISPR-Cas9 was the gene-editing tool. CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats, is a naturally occurring defense system in bacteria that scientists have adapted for gene editing. The Cas9 enzyme acts like molecular scissors, cutting DNA at specific locations. A guide RNA directs Cas9 to the target sequence. Once cut, the cell’s natural repair mechanisms can insert, delete, or alter genetic material.
He targeted the CCR5 gene, encoding a protein on white blood cells that HIV uses to enter cells. A naturally occurring mutation, CCR5-Δ32, involves a 32 DNA base pair deletion in this gene, resulting in a non-functional protein and conferring HIV resistance. He aimed to mimic this protective mutation.
However, modifications to Lulu and Nana’s CCR5 genes were not the exact 32-base pair deletion of the natural CCR5-Δ32 mutation and varied between the twins. One twin had only one copy modified, the other had both altered, though not as intended. The presence of edited and unedited cells (mosaicism) also raised questions about effectiveness.
International Outcry and Ethical Debates
The announcement of the gene-edited twins ignited widespread condemnation from the global scientific and ethical communities. A primary concern was germline editing, which involves heritable changes to embryos. This raised questions about unforeseen health consequences for the children and their descendants due to off-target or unintended genetic alterations. Many scientists and ethicists argued that such an intervention lacked medical necessity, especially given existing, safer methods to prevent HIV transmission from an HIV-positive father to a child, such as sperm washing and in vitro fertilization.
Questions were also raised regarding the informed consent process for the parents, with many doubting whether they fully understood the experimental nature of the procedure and the potential risks involved. International bodies and researchers agreed the experiment was premature, irresponsible, and violated ethical guidelines, as human germline editing was not ready for clinical application. Over 100 Chinese scientists condemned the work as “crazy” and a “huge blow” to Chinese science’s reputation.
Regulatory Aftermath and Scientific Repercussions
Chinese authorities swiftly suspended He Jiankui’s research activities after his presentation. In December 2019, a Chinese court found He Jiankui guilty of illegal medical practice, sentencing him to three years in prison and a 3 million yuan (approximately $430,000 USD) fine. Two collaborators, Zhang Renli and Qin Jinzhou, received lesser sentences. The court stated the accused “deliberately violated national regulations in scientific research and medical treatment” and “crossed the bottom line of ethics.”
The incident significantly impacted gene editing research worldwide, leading to renewed calls for stricter international oversight and clearer human germline editing guidelines. China subsequently unveiled draft regulations categorizing gene editing as “high-risk” technology, requiring State Council health department management. The event also influenced public perception of gene editing, raising concerns about misuse and the need for robust ethical frameworks.