The term “CRISPR babies” refers to human infants whose genetic makeup has been deliberately altered using CRISPR technology. This genetic modification in human embryos has sparked considerable discussion due to its implications for human health and society.
Understanding CRISPR Gene Editing
CRISPR-Cas9 technology, derived from a natural bacterial defense system, allows for precise modifications to DNA. This system functions like molecular scissors, guided by a synthetic RNA molecule to a specific DNA sequence in the genome. The Cas9 enzyme then creates a double-strand break at that location.
Once the DNA is cut, the cell’s natural repair mechanisms can be harnessed to either disable a gene or insert new genetic material. This process can lead to two types of modifications: disabling a gene (knockouts) or introducing new genetic sequences (knock-ins).
Gene editing can be categorized into somatic cell editing and germline editing. Somatic cell editing affects only the individual treated, with changes not passed on to future generations. In contrast, germline gene editing modifies DNA in reproductive cells (sperm, eggs) or early embryos, meaning these changes can be inherited by subsequent generations. The “CRISPR babies” controversy involves germline gene editing, as these genetic alterations become a permanent part of the human gene pool.
The Landmark Case of the First CRISPR Babies
The global scientific community reacted strongly in November 2018 to the announcement of the birth of the first gene-edited babies. Chinese scientist He Jiankui disclosed that he had used CRISPR-Cas9 to modify the genes of twin girls, named Lulu and Nana. The embryos were from couples undergoing in vitro fertilization, where the male partner was HIV-positive and the female partner was HIV-negative.
He Jiankui’s purpose was to confer resistance to HIV by targeting the CCR5 gene. This gene codes for a protein that HIV uses to enter and infect white blood cells. Individuals with a naturally occurring deletion in the CCR5 gene, known as CCR5Δ32, exhibit resistance to certain strains of HIV.
He introduced the gene-editing components into the embryos at their creation. However, further analysis indicated the edits were not always as intended, resulting in novel mutations rather than the precise CCR5Δ32 deletion. The experiment was condemned by scientists worldwide due to concerns about safety, medical necessity, and the premature application of the technology.
Ethical and Societal Considerations
Germline gene editing introduces a range of complex ethical and societal dilemmas. One concern is the concept of “designer babies,” where gene editing could theoretically be used for non-medical enhancements, raising questions about societal values and human diversity. The ability to select for certain traits could exacerbate social inequalities if the technology is only accessible to affluent individuals, potentially creating a “genetic divide.”
Concerns also exist about unintended off-target effects, where the CRISPR system might make edits at locations other than the intended gene, leading to unforeseen health consequences for the individual and their descendants. The long-term impacts of altering the human germline on human evolution and genetic diversity are not yet fully understood. Another concern is the issue of consent for future generations, as individuals whose genes are altered as embryos cannot provide their own consent.
International Scientific and Regulatory Landscape
The advent of germline gene editing has prompted various responses from scientific organizations, governments, and international bodies. Many scientific groups have called for moratoria or strict guidelines for germline editing, stressing the need for further research into safety and efficacy before clinical application. The World Health Organization (WHO) issued recommendations on human genome editing in 2021, though no international law currently governs the matter.
Regulations regarding germline editing vary significantly across countries. Some nations have outright prohibitions, while others have strict regulations or a lack of specific laws. For instance, the European Union’s Charter of Fundamental Rights prohibits “eugenic practices,” and the Oviedo Convention generally requires that genome modifications be for therapeutic purposes, not for altering descendants’ genomes. China, following the He Jiankui case, updated its criminal code to make the implantation of gene-edited embryos punishable by prison time. Efforts continue to establish global consensus and responsible governance frameworks.