Cloning involves creating an exact genetic copy of a biological entity, such as a cell, a segment of DNA, or an entire organism. This process can occur naturally, as seen in asexual reproduction among certain plants and bacteria, or artificially through biotechnological methods. Applying these techniques to humans has sparked discussion and inquiry regarding both feasibility and implications.
The Science of Cloning
The primary scientific method for artificial cloning is Somatic Cell Nuclear Transfer (SCNT). This technique begins by taking a somatic cell, which is any body cell other than a reproductive cell, from the donor organism. The nucleus, containing the donor’s genetic information, is then removed from this somatic cell.
Simultaneously, an unfertilized egg cell, or oocyte, is obtained from a different individual. The nucleus of this egg cell is removed, creating an “enucleated” egg. The donor somatic cell nucleus is then transferred into this enucleated egg. This new cell, now containing the donor’s genetic blueprint, is stimulated, often with an electrical pulse, to begin dividing and developing as if it were a fertilized zygote.
If the activated egg develops into an early-stage embryo, known as a blastocyst, it can be used for various purposes. A notable achievement using SCNT was the creation of Dolly the sheep in 1996 by scientists at the Roslin Institute in Scotland. Dolly was the first mammal cloned from an adult somatic cell, a mammary gland cell, demonstrating that specialized adult cells could be reprogrammed to create an entire new organism. This breakthrough showed that the DNA in an adult cell’s nucleus could revert to an embryonic state, capable of developing into all cell types of an animal.
Where Human Cloning Stands Today
While animal cloning using SCNT has advanced, creating a full human being through reproductive cloning has not been successfully achieved. Human cloning falls into two categories: therapeutic and reproductive. Therapeutic cloning creates embryonic stem cells genetically identical to a patient, aiming to produce healthy tissue for medical treatments and research. This type of cloning has been achieved in humans, with successes reported as early as 2013 using fetal and infant skin cells, and improved in 2014 with adult patient skin cells.
Reproductive cloning, which aims to create a complete human individual, faces substantial technical and biological challenges. The success rates for SCNT in mammals are generally very low, with many attempts resulting in developmental abnormalities or failure to develop beyond early embryonic stages. For instance, Dolly the sheep’s creation involved 277 attempts, with only one successful birth. Challenges include difficulties isolating high-quality somatic cells and enucleating egg cells without damage, as well as the risk of abnormal development due to incomplete genetic reprogramming. Even if a cloned human embryo were to develop, concerns exist about potential health issues like premature aging or organ defects.
Ethical and Societal Questions
The prospect of human cloning, particularly reproductive cloning, raises complex ethical and societal questions. A concern revolves around human dignity and individuality. Critics suggest that creating a genetically identical copy might undermine a person’s unique identity, leading to psychological issues for the cloned individual who may face constant comparison to their genetic “original.” This process could potentially reduce individuals to their genetic makeup, raising questions about their autonomy and self-perception.
There are also concerns about the potential for exploitation, particularly regarding women pressured to donate eggs for cloning procedures. The process of obtaining eggs often involves hormone treatments, which carry health risks. The commodification of human life is another worry, as the possibility of creating individuals for specific purposes or financial gain challenges established moral boundaries. These ethical debates extend to the definition of family and kinship, as reproductive cloning would introduce new dynamics diverging from traditional biological relationships.
Global Legal Approaches
The global legal landscape reflects a widespread consensus against reproductive human cloning. Many countries have enacted laws to prohibit it due to ethical and safety concerns. For example, the United Kingdom’s Human Reproductive Cloning Act 2001 makes it an offense to implant an embryo created by any means other than fertilization into a woman, with penalties including imprisonment and fines. This legislation effectively bans reproductive cloning in the UK.
The international community has also addressed the issue, with the United Nations General Assembly adopting the non-binding UN Declaration on Human Cloning in March 2005. This declaration calls upon member states to prohibit all forms of human cloning “incompatible with human dignity and the protection of human life.” While non-binding, it reflects a broad international stance against reproductive human cloning. Some countries, like the UK, permit therapeutic cloning under strict regulations, highlighting a nuanced approach that differentiates between creating embryos for research and for reproductive purposes.