‘Reproductive’ and ‘therapeutic’ cloning: What’s the difference?

Mar 2003    


A RECENT article in The Straits Times announced the intention of a group of researchers at the National University of Singapore to clone a human embryo for research (Straits Times, Wednesday, Dec 25, 2002, H8). This announcement was made in the wake of a similar initiative to be undertaken by scientists from the prestigious Stanford University, the first attempted by a United States university.

Commenting on the objective of therapeutic cloning, Professor Ng, who heads the NUS team of researchers, told The Straits Times: “My team hopes to develop cells through nuclear transfer for clinical trials in patients with irreversible brain or spinal damage, and possibly in diabetes and liver diseases.” He added that he and his team were “not interested in human productive cloning, nor are we allowed to do so”.

This position is in line with that of the Bioethics Advisory Committee (BAC) whose recommendations on ES Cell Research were accepted by the Singapore Government. In its report, the BAC makes the distinction between “therapeutic cloning” and “reproductive cloning”. While opposing reproductive cloning, the BAC recommended that therapeutic cloning be allowed under stringent conditions.

Much depends on the difference between “reproductive” and “therapeutic cloning”. Reproductive cloning, according to some scientists, is the process by which an embryo is created by nuclear transfer and implanted into a woman’s womb in the hope of bringing it to term. Therapeutic cloning, on the other hand, is the process by which an embryo is created through nuclear transfer in order to obtain stem cells from it. The preparation of human embryonic stem cells by therapeutic cloning requires the development of the embryo to the stage of initial blastocyst. The embryoblast or inner mass (ICM) is then isolated – a process that implies the destruction of the embryo – and cultured on a feeder.

According to the above definitions, the distinction between the “reproductive” and “therapeutic” cloning has to do with the purposes to which the clone will be put to use and not the nature of the clone. In either case, an embryo is cloned. In either case, one is dealing with the reality of a human being, who is the subject of human rights, the most fundamental of which is the right to live.

This raises the question whether the blastocyst is indeed a human being who must be accorded with the same rights and dignity as every human being. Scientists who maintain that human life begins at about 14 days when “individuation” occurs have made the distinction between a “re-embryo” and an “embryo”. These and other euphemisms that have entered the discussion – “totipotent cell”, “clump of embryonic cells”, “unfertilised oocyte”, etc – have clouded the issue. Thus, scientists who oppose the cloning of “human beings” and “persons” reserve the right to clone embryos or blastocysts as long as they are not allowed to survive to birth.

Scripture and tradition hold that life begins from conception, and that the embryo, from the moment it is formed from the union of the gametes, is a human subject with a well-defined identity. Therefore the zygote, from its conception, is a human being made in the image of God and should therefore be accorded the same respect and dignity as all human beings.

This position can be defended philosophically as well as scientifically. It can be argued that the human zygote is a human being because it cannot articulate itself into some other animal. Conversely, it can be argued that the human zygote will articulate itself into a mature human being because it is already one from its conception. There are many established embryologists and scientists who hold that human life begins at conception.

Writes Marjorie England: “Development of the embryo begins at Stage 1when a sperm fertilises an oocyte and together they form a zygote.” In similar vein Keith Moore maintains that “human development begins after the union of male and female gametes or germ cells during a process known as fertilisation (conception).” In “Cloning Human Beings”, a report of the National Bioethics Advisory Commission in Rockville, an embryo is defined as “the developing organism from the time of fertilisation until significant differentiation has occurred, when the organism becomes known as a fetus”.

‘No’ to sacrifice a human life for benefit of others


William Larsen describes the zero point of embryonic development thus: “The chromosomes of the oocyte and sperm are … respectively enclosed within female and male pronuclei. These pronuclei fuse with each other to produce the single, diploid, 2N nucleus of the fertilised zygote. This moment of zygote formation may be taken as the beginning or zero time point of embryonic development.” “If it’s not an embryo,” Jonathan Van Blerkom, the embryologist at University of Colorado asks, “what is it?”

Finally, in “Human Embryology & Teratology”, Ronan O’Rahilly and Fabiola Müller contend that “although life is a continuous process, fertilisation is a critical landmark because, under ordinary circumstances, a new genetically human organism is thereby formed … The combination of 23 chromosomes present in each pronucleus results in 46 chromosomes in the zygote. Thus the duploid number is restored and the embryonic genome is formed. The embryo now exists as a genetic unity.”

This textbook describes “pre-embryo” as “ill-defined and inaccurate” and lists it among “discarded and replaced terms”. This chorus of voices should at least caution against regarding too hastily what appears to be an abstract and arbitrary distinction as a dogma that has achieved widespread consensus among members of the scientific community.

The refrain that “the advantages of therapeutic cloning or embryonic stem cell research to mankind far outweighs the ethical considerations” has been repeated so often that it has almost become axiomatic. Killing a healthy adult and quarrying his organs for transplant may save the lives of numerous others who will otherwise die. It may be argued that the therapeutic potentials and advantages (saving numerous lives) far outweigh the ethical considerations (taking the life of just one human being). But no society would countenance this utilitarian calculus that prizes the lives of many over the life of one human being. Yet, scientists could without difficulty apply this principle to human embryos.

From the standpoint of Christian ethics it is never ethical to sacrifice one human life for the real or potential benefit of others. No end can be deemed good if the means by which it is achieved is itself wrong. The human embryo is a living human being from the moment of conception, and therefore, it has inviolable dignity. It must not be treated as a means to an end: it is an end in itself.

It merits our fullest respect, the same respect that we accord to the newborn babe, the child, the adolescent, and the adult. It may not be cloned and killed in order that parts of its body may be used for the benefit of another person.

Dr Roland Chia, a lecturer at Trinity Theological College, is also the Director of the Centre for the Development of Christian Ministry at TTC. He is a member of Fairfield Methodist Church.


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