The news broke in late 2018 that Chinese scientist He Jiankui claimed to have genetically modified human embryos, resulting in live births. He announced the creation of the world’s first gene-edited human babies, twin girls known by the pseudonyms Lulu and Nana. This revelation instantly became one of the most significant and controversial scientific events of the 21st century. It sparked a global debate, forcing a confrontation with the ethical limits of technological progress and establishing a precedent for human germline modification.
The Announcement and the Immediate Aftermath
The public revelation of the gene-editing experiment was a secretive, last-minute announcement designed to preempt the Second International Summit on Human Genome Editing in Hong Kong. The story broke on November 25, 2018, confirmed by He Jiankui, then a faculty member in Shenzhen, through a series of online videos. This news sent a shockwave through the global scientific community assembled for the summit.
When He Jiankui took the stage on November 28, his peers reacted with immediate condemnation. Researchers expressed deep concern over the lack of transparency surrounding the trial. Chinese authorities responded swiftly to the global outcry, launching an investigation and ordering a halt to all of He Jiankui’s research activities. The scientific consensus viewed the procedure as reckless and premature.
The Science Behind the Gene Editing
The technology employed by He Jiankui’s team was Clustered Regularly Interspaced Short Palindromic Repeats, or CRISPR/Cas9. This tool allows scientists to make precise changes to DNA sequences. CRISPR uses a guide RNA to locate a specific target sequence in the genome, where the Cas9 enzyme then makes a cut, enabling the removal or insertion of genetic material. The specific target of the editing in the embryos was the CCR5 gene.
The CCR5 gene encodes a protein on the surface of white blood cells that HIV uses to infect cells. He Jiankui aimed to disable this gene to confer resistance to HIV infection, mimicking the naturally occurring CCR5-Δ32 mutation. This modification was performed on the embryos at the single-cell stage before implantation.
This work involved germline editing, meaning the genetic alteration was made in the embryo and is inheritable by all future generations. This differs from somatic editing, which changes DNA only in non-reproductive cells and cannot be passed on. Analysis of the twins’ genetic data revealed the editing was incomplete, resulting in mosaicism, where not all cells carry the edit. In neither twin did the editing exactly reproduce the protective CCR5-Δ32 mutation, raising concerns about unintended “off-target” effects.
Global Ethical and Regulatory Condemnation
The experiment drew ethical and regulatory condemnation because it violated international consensus against non-therapeutic germline editing. A significant ethical failing was the lack of adequate medical indication for the procedure. Although the fathers were HIV-positive, the mothers were HIV-negative, and established procedures like sperm washing already prevent HIV transmission to the child, eliminating any medical necessity.
The process also suffered from a profound failure of research ethics regarding informed consent. Reports indicated the couples were not fully informed of the procedure’s risks or that the research was highly controversial and prohibited. The court later found that He Jiankui had forged the necessary ethics review documents, demonstrating a deliberate evasion of oversight. The international community, including the World Health Organization (WHO), called the actions a violation of medical ethics.
Editing the human germline was viewed as crossing a fundamental line, introducing changes that could affect the human gene pool without understanding the long-term consequences. Critics noted that the CCR5 gene is linked to other biological functions, such as resistance to West Nile and influenza, meaning the modification could create new health vulnerabilities. This event spurred urgent calls for moratoria and stricter international regulations on human genome editing.
Legal Consequences and Current Status of He Jiankui
The fallout from the experiment led to legal and professional consequences for He Jiankui in China. In December 2019, a Chinese court in Shenzhen sentenced him to three years in prison and imposed a fine of 3 million yuan (approximately $430,000). He was convicted of “illegal medical practice” for deliberately violating national regulations and ethical principles.
He Jiankui was released from prison in April 2022 after completing his full sentence. Following his release, he announced the establishment of a new laboratory to focus on gene therapies for rare diseases, such as Duchenne muscular dystrophy. This move generated renewed debate regarding the appropriate professional future for a researcher who disregarded ethical boundaries.
The current status and health of the gene-edited children—the twin girls Lulu and Nana, and a third baby born later in 2019—remain largely unknown. Chinese authorities have maintained secrecy regarding the children’s location and well-being, citing privacy concerns. The scientific community continues to stress the need for long-term, independent medical monitoring to assess the full impact of the genetic modifications on the children’s health.