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The question of whether or not human cloning is ethical

Percent of Americans born between 1840 and 1960 surviving to ages 15 and 45 It might seem at first that selection due to differential fertility has been considerably reduced in industrial countries as a consequence of the reduction in the average number of children per family that has taken place. However, this is not so. The intensity of fertility selection depends not on the mean number of children per family, but on the variance in the number of children per family.

It is clear why this should be so. Assume that all people of reproductive age marry and that all have exactly the same number of children. In this case, there would not be fertility selection whether couples all had very few or all had very many children. Assume, on the other hand, that the mean number of children per family is low, but some families have no children at all or very few, whereas others have many.

In this case, there would be considerable opportunity for selection—the genotypes of parents producing many children would increase in frequency at the expense of those having few or none. Studies of human populations have shown that the opportunity for natural selection often increases as the mean number of children decreases.

An extensive study published years ago showed that the index of opportunity for selection due to fertility was four times larger among United States women born in the 20th century, with an average of less than three children per woman, than among women in the Gold Coast of Africa or in rural Quebec, who had three times or more children on average Table 2 811.

There is no evidence that natural selection due to fertility has decreased in modern human populations. View popup Table 2. Mean number of children per family and index of opportunity for fertility selection If, in various human populations Natural selection may decrease in intensity in the future, but it will not disappear altogether.

As long as there is genetic variation and the carriers of some genotypes are more likely to reproduce than others, natural selection will continue the question of whether or not human cloning is ethical in human populations.

The global governance of human cloning: the case of UNESCO

Cultural changes, such as the development of agriculture, migration from the country to the cities, environmental pollution, and many others, create new selective pressures. The pressures of city life are partly responsible for the high incidence of mental disorders in certain human societies. The point to bear in mind is that human environments are changing faster than ever owing precisely to the accelerating rate of cultural change, and environmental changes create new selective pressures, thus fueling biological evolution.

Natural selection is the process of differential reproduction of alternative genetic variants. In terms of single genes, variation occurs when two or more alleles are present in the population at a given gene locus. How much genetic variation exists in the current human population? The two genomes that we inherit from each parent are estimated to differ at about one or two nucleotides per thousand.

The human genome consists of somewhat more than 3 billion nucleotides 12. Thus, about 3—6 million nucleotides are different between the two genomes of each human individual, which is a lot of genetic polymorphism. Moreover, the process of mutation introduces new variation in any population every generation.

Thus, every human has about 60 new mutations 30 in each genome that were not present in the parents. If the question of whether or not human cloning is ethical consider the total human population, that is 60 mutations per person multiplied by 7 billion people, which is about 420 billion new mutations per generation that are added to the preexisting 3—6 million polymorphic nucleotides per individual.

That is a lot of mutations, even if many are redundant. Moreover, we must remember that the polymorphisms that count for natural selection are those that impact the probability of survival and reproduction of their carriers. Genetic Disorders More than 2,000 human diseases and abnormalities that have a genetic causation have been identified in the human population. Genetic disorders may be dominant, recessive, multifactorial, or chromosomal.

Dominant disorders are caused by the presence of a single copy of the defective allele, so that the disorder is expressed in heterozygous individuals: In recessive disorders, the defective allele must be present in both alleles, that is, it is inherited from each parent to be expressed.

Multifactorial disorders are caused by interaction among several gene loci; chromosomal disorders are due to the presence or absence of a full chromosome or a fragment of a chromosome 1415. Examples of dominant disorders are some forms of retinoblastoma and other kinds of blindness, achondroplastic dwarfism, and Marfan syndrome which is thought to have affected President Lincoln.

Cloning humans? Biological, ethical, and social considerations

Examples of recessive disorders are cystic fibrosis, Tay-Sachs disease, and sickle cell anemia caused by an allele that in heterozygous condition protects against malaria. Examples of multifactorial diseases are spina bifida and cleft palate.

  • One common view among those who hold the intermediate moral status view is that the use of discarded IVF embryos to obtain stem cells is compatible with the respect we owe to the embryo, whereas the creation and use of cloned embryos is not;
  • These differences turn largely, though not exclusively, on different judgments regarding the nature and moral status of the early human cloned embryo;
  • Natural selection has no purpose; humans alone have purposes and they alone may introduce them into their evolution;
  • We can imagine, in advance of any discussion, a variety of moral opinions that would emerge, influenced in part by how the question is formulated;
  • Parents can replace a dying child with a genetically identical new one;
  • It took hundreds of tries to clone Dolly.

Among the most common chromosomal disorders are Down syndrome, caused by the presence of an extra chromosome 21, and various kinds due to the absence of one sex chromosome or the presence of an extra one, beyond the normal condition of XX for women and XY for men.

The incidence of genetic disorders expressed in the living human population is estimated to be no less than 2. Natural selection reduces the incidence of the genes causing disease, more effectively in the case of dominant disorders, where all carriers of the gene will express the disease, than for recessive disorders, which are expressed only in homozygous individuals.

Consider, for example, phenylketonuria PKUa lethal disease if untreated, due to homozygosis for a recessive gene, which has an incidence of 1 in 10,000 newborns or 0. PKU is due to an inability to metabolize the amino acid phenylalanine with devastating mental and physical effects. A very elaborate diet free of phenylalanine allows the patient to survive and reproduce if started early in life. The reduction of genetic disorders due to natural selection is balanced with their increase due to the incidence of new mutations.

Hereditary retinoblastoma is a disease attributed to a dominant mutation of the gene coding for the retinoblastoma protein, RB1, but it is actually due to a deletion in chromosome 13. The unfortunate child with this condition develops a tumorous growth during infancy that, without treatment, starts in one eye and often extends to the other eye and then to the brain, causing death before puberty. Surgical treatment now makes it possible to save the life of the child if the condition is detected sufficiently early, although often one or both eyes may be lost.

The treated person can live a more or less normal life, marry, and procreate. However, because the genetic determination is dominant a gene deletionone half of the the question of whether or not human cloning is ethical will, on the average, be born with the same genetic condition and will have to be treated. Before modern medicine, every mutation for retinoblastoma arising in the human population was eliminated from the population in the same generation owing to the death of its carrier.

With surgical treatment, the mutant condition can be preserved, and new mutations arising each generation are added to those arisen in the past refs. The proportion of individuals affected by any one serious hereditary infirmity is relatively small, but there are more than 2,000 known serious physical infirmities determined by genes.

The problem becomes more serious when mental defects are taken into consideration. More than 100 million people in the world suffer from mental impairments due in good part to the genetic endowment they inherited from their parents. Natural selection also acts on a multitude of genes that do not cause disease.

  • The most permissive among them urge great caution in using this kind of genetic manipulation;
  • Environment, especially family environment, is still a major influence on the persons we become;
  • Moreover, there are other ways that the pursuit of utility and autonomy are troubling from a theological perspective;
  • They contain short segments of DNA;
  • There is only space here to note two of the many that weigh heavily against human cloning.

Genes impact skin pigmentation, hair color and configuration, height, muscle strength and body shape, and many other anatomical polymorphisms that are apparent, as well as many that are not externally obvious, such as variations in the blood groups, in the immune system, and in the heart, liver, kidney, pancreas, and other organs.

It is not always known how natural selection impacts these traits, but surely it does and does it differently in different parts of the world or at different times, as a consequence of the development of new vaccines, drugs, and medical treatments, and also as a consequence of changes in lifestyle, such as the reduction of the number of smokers or the increase in the rate of obesity in a particular country.

  • No one is better situated to appreciate these truths than the physician;
  • Although the embryo's cells contain the same genetic code as the cells of the adult being cloned, the embryo must go through many years of development in an environment that is significantly different from that in which the adult developed;
  • Offering individuals or couples the possibility to reproduce using cloning technology has been said to be consistent with the right to reproductive freedom, which, according to some, implies the right to choose what kind of children we will have Brock 1998, 145.

Genetic Therapy Where is human evolution going? Biological evolution is directed by natural selection, which is not a benevolent force guiding evolution toward sure success.

Natural selection brings about genetic changes that often appear purposeful because they are dictated by the requirements of the environment. The end result may, nevertheless, be extinction—more than 99. Natural selection has no purpose; humans alone have purposes and they alone may introduce them into their evolution.

No species before mankind could select its evolutionary destiny; mankind possesses techniques to do so, and more powerful techniques for directed genetic change are becoming available. Because we are self-aware, we cannot refrain from asking what lies ahead, and because we are ethical beings, we must choose between alternative courses of action, some of which may appear as good and others as bad.

The argument has been advanced that the biological endowment of mankind is rapidly deteriorating owing precisely to the improving conditions of life and to the increasing power of modern medicine. The detailed arguments that support this contention involve some mathematical exercises, but their essence can be simply presented. The great majority of newly arising mutations are either neutral or harmful to their carriers; only a very small fraction are likely to be beneficial.

The more harmful the effect of a mutation, the more rapidly it will be eliminated from the population by the question of whether or not human cloning is ethical process of natural selection. However, owing to medical intervention and, more recently, because of the possibility of genetic therapy, the elimination of some harmful mutations from the population is no longer taking place as rapidly and effectively as it did in the past. Molecular biology has introduced in modern medicine a new way to cure diseases, namely genetic therapy, direct intervention in the genetic makeup of an individual.

Gene therapy can be somatic or germ line. Germ-line genetic therapy would seek to correct a genetic defect, not only in the organs or tissues impacted, but also in the germ line, so that the person treated would not transmit the genetic impairment to the descendants.

As of now, no interventions of germ-line therapy are seriously sought by scientists, physicians, or pharmaceutical companies. The possibility of gene therapy was first anticipated in 1972 20.

The possible objectives are to correct the DNA of a defective gene or to insert a new gene that would allow the proper function of the gene or DNA to take place. In the case of a harmful gene, the objective would be to disrupt the gene that is not functioning properly. The eminent biologist E. The first successful interventions of gene therapy concerned patients suffering from severe combined immunodeficiency SCIDfirst performed in a 4-y-old girl at the National Institutes of Health in 1990 22soon followed by successful trials in other countries 23.

Treatments were halted temporarily from 2000 to 2002 in Paris, when 2 of about 12 treated children developed a leukemia-like condition, which was indeed attributed to the gene therapy treatment. The question of whether or not human cloning is ethical therapy treatments are still considered experimental. Initially, the prevailing gene therapy methods involved recombinant viruses, but nonviral methods transfection molecules have become increasingly successful.

However, in addition to the huge economic costs, technical hurdles remain. Frequent negative effects include immune response against an extraneous object introduced into human tissues, leukemia, tumors, and other disorders provoked by vector viruses. Moreover, the genetic therapy corrections are often short lived, which calls for multiple rounds of treatment, thereby increasing costs and other handicaps.

In addition, many of the most common genetic disorders are multifactorial and are thus beyond current gene therapy treatment. If a genetic defect is corrected in the affected cells, tissues, or organs, but not in the germ line, the ova or sperm produced by the individual will transmit the defect to the progeny.

A deleterious gene that might have been reduced in frequency or eliminated from the population, owing to the death or reduced fertility of the carrier, will now persist in the population and be added to its load of hereditary diseases.

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A consequence of genetic therapy is that the more hereditary diseases and defects are cured today, the more of them will be there to be cured in the succeeding generations. This consequence follows not only from gene therapy but also from typical medical treatments. The Nobel laureate geneticist H. Muller eloquently voiced this concern about the cure, whether through genetic therapy or traditional medical treatment, of genetic ailments.

For everyone would be an invalid, with his own special familial twists….