Human Cloning and its Challenges
Cloning isn’t a science fiction fantasy but a living reality in today’s world. Cloning in its simplest form is duplicating biological material -such as a cell or a piece of DNA- for scientific study. In this article, we will discuss some of the main challenges that face various types of cloning and how these challenges haven’t been resolved.
Early Experiments in Cloning
Briggs and King (1952) successfully cloned tadpoles from embryonic DNA taken from the frog species Rana Pipiens. Scientists in the 1970s used Recombinant DNA - taking DNA from two separate organisms and combining them to make a new artificial organism - and made transgenic clones by extracting DNA material from other organisms. Advances in cloning techniques in the 1980s allowed researchers to clone mammals and sheep from early and partially differentiated embryonic cells.
There was limited success in human cloning using the Somatic cell nuclear transfer process. Eventually, the process allowed for identical genetic cloning of a full-grown sheep. (Rugnetta, 2022)
Reproductive cloning is the implantation of a cloned embryo into a natural or artificial uterus which is then carried to term.
In the 1990s the cloning process was revolutionized with the creation of “DOLLY” the first genetically cloned sheep who lived from 1997 to 2003. The debate over the abuses of mammal genetic cloning and the morality of the technology began as supporters and detractors argued the pros and cons of reproductive cloning. The creation of Dolly refined reproductive cloning as it became known as Somatic cell nuclear transfer and re-established pluripotency. Pluripotency is the process by which an embryonic cell can grow into various mature body cells making a complete organism. In California, scientists announced in 2007, that they had cloned human embryos using SCNT but destroyed them after 5 days.
Reproductive cloning is too dangerous to be a viable cloning process. Fetuses grown from reproductive cloning rarely survive gestation and if they do survive gestation they most likely will have birth defects. The scientists who created Dolly attempted 277 cloning experiments before a fetus survived gestation. Dolly was successfully cloned and she grew into an adult sheep. Other cloning experiments failed when scientists cloned 100 Macaque monkey embryos and inserted them into 50 female Macaque monkeys. None of these monkeys developed viable pregnancies.
Therapeutic Cloning removes stem cells from cloned embryos without implanting the embryos into the wombs.
Stem cells may be stimulated to differentiate into any of the more than 200 cells in the human body. If the process is successful then these cloned cells could be injected into the human body to treat many diseases including Alzheimer's disease, Parkinson's disease, diabetes mellitus, stroke, and spinal cord injury.
The reality is that cloned stem cells from mice embryos have been taken but from primate embryos, the taking of stem cells and their generation has been difficult to achieve. Human stem cell development is out of the question at this time.
Scientists at Advanced Cell Technology in 2001 were able to transfer human cumulus cells- cells that cling to and nourish human eggs- into 8 enucleated eggs. These are eggs having their nucleus removed, three of which developed into early-stage human embryos. These embryos developed 4 of 6 cells and only divided twice and then died. Ultimately, the process was a failure.
Realistically, human therapeutic cloning has been extremely slow in comparison to animal cloning. The prospect of therapeutically cloning human beings doesn’t look promising. This has raised ethical questions such as:
- Safety and efficacy of the cloning procedure
- Cloning for destructive embryonic stem cell research
- The effects on the parent and child relationship from reproduction cloning
- Commercializing human life as a research product
There have been many objections raised about continuing therapeutic cloning. Including the slow progression of cloning human embryos, human embryos dying after dividing twice, and the embryos not progressing beyond the early stages of development.
The Ethical Implications of Cloning
The probability of loss of life in human cloning is great, bringing up the issue of loss of life for experimental purposes. The international community feels that cloning is too risky because of the potential for the loss of human life. Who has the power to decide if a cloned fetus should be destroyed or not in the experimental process and at what point in the cloning process is life truly defined?
Reproductive cloning has been internationally condemned as inhuman and immoral. The cloned fetus must be inserted into the fetus but only after extensive molecular testing has been done. The woman’s body could potentially reject the cloned fetus as the birthing process doesn’t take its natural course. The mother’s life may be in jeopardy because there is no guarantee that her immune system will not kill the fetus. The immune system may perceive the cloned fetus as an attacking agent out to destroy the mother’s life.
Intervention by the United Nations
The United Nations passed a Declaration of Human Cloning in 2005. The declaration states that all measures should be adopted to terminate human cloning to protect the integrity of life but this declaration is non-binding on the international community. Cloning has some major hurdles to overcome to be a viable scientific process and the ethical and philosophical challenges are far from being resolved in the 21st century. The international community will not embrace cloning on a universal scale yet.
2000, Julian(YOEL) Jakobovits, "Cloning and Its Challenges," The Torah U-Madda Journal.
2007, Anthony J.F. Griffiths, "Recombinant DNA" Genetic Engineering Britannica Encyclopedia.
2010, Megan Kearl, "Dickey-Weber Amendment" The Embryo Project Encyclopedia.
2022, Michael Rugnetta, "Cloning Genetics" Encyclopedia Britannica.