Text IX what is down syndrome?

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If you are like most people, you probably had little understanding of what Down syndrome meant before your baby was born. Basically, Down syndrome means that your baby has one extra chromosome each of his millions of cells. Instead of forty-six, he has forty-seven. Over six thousand babies with Down syndrome are born in the United States every year and thousands more in other countries. It is one of the most common birth defects. Everyone has heard of children born with other disorders, such as spina bifida, cerebral palsy, muscular dystrophy, and Tay-Sachs disease. Of these, only cerebral palsy is more common than Down syndrome. Other chromosomal disorders are far less common.

Because genes and chromosomes play a large part in determining your child's characteristics, this extra chromosome will affect his life. His appearance may be a bit different from other children, he may have some unique medical problems, and he will likely have some degree of mental retardation, although the severity of any of these problems varies tremendously from child to child.

Two things about Down syndrome are clear. First; parents do not cause Down syndrome; nothing you did or did not do before or during pregnancy caused your baby to have Down syndrome. Second, like "normal" children, each baby with Down syndrome is unique, with his own personality, talents, and thoughts. There are few absolutes governing your baby's destiny like other children, he is an individual and will grow to become a distinct personality.

Parents frequently are amazed at how often conception results in abnormal chromosomes. In general, chromosomal abnormalities of one kind or another may occur in as many as four in one hundred conceptions. Most of these pregnancies end in miscarriage. In fact, a quarter of all miscarriages result from chromosomal abnormalities that do not allow the embryo to develop.

Down syndrome, the most common chromosomal abnormality in humans, is one that does allow the embryo to develop. Down syndrome occurs in all races and in all countries. Recent figures place the frequency in North America at about one in eight hundred to one in one thousand births. It can happen to anyone. It happens in both girls and boys evenly.

(Babies with Down Syndrome. – London, 1986. – 25 p.)

Text X genetics

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The New York Times reported that for the first time in history, researchers had mapped one of the 23 pairs of chro­mosomes that make up every cell in the human body.

Once all of the genes in the human body are mapped, the genetic roots of diseases, disabilities, and various physical traits can be identified. But, as DAA notes in it's submission to the World Health Organization (WHO) Consultation: Ethical Issues in Cloning & Biotechnology, the current appli­cation of this research tends less toward exploring cures for diseases and more toward eugenics, the science of improving the human race through selective breeding. Using genetic testing to verify that certain conditions are present in a fetus results not in new methods to treat or eliminate the disor­ders but in the abortion of babies that are perceived as having defects.

Prenatal testing, the screening of foetal cells for genetic problems, has traditionally been done in some countries when parents fear their foetus is at risk for a certain condition. In the future, older testing methods such as amniocentesis will be replaced by the genetic screening of foetal cells ^pm the mother's blood sample. Moreover, the reproductiye, tech­nology (medically assisted ways of conceiving children) now used in some countries will be supplemented by more radical methods. In vitro fertilization, in which eggs taken from a woman's body are combined with sperm in a labora­tory in hopes of producing a fertilized egg or embryo, has already been paired with ex utero genetic testing in some countries. In ex utero genetic testing, cells are taken from the embryo for DNA analysis—and only embryos that do not carry unwanted genetic traits are implanted in the woman's uterus. Given the choice and the ability, people may very well decide to have only the children that meet their expectations for the perfect baby.

For some people, the best way to conceive the perfect baby may be through cloning, a technique that produces an organism that is genetically identical to a parent. In 1997°Scottish scien­tists announced the birth of a sheep named Dolly who had been cloned from the cell of another adult female sheep. Several other successful cloning experiments followed soon after this discovery, including the production of an embryo from the cells of a woman in the Republic of Korea. Human cloning seems destined to become a real option in the field of reproductive technology despite the questions it raises about giving humans control over the evolution of their race.

These questions are the current study of bioethicists, or those who examine moral issues that arise in medical treat­ment and research.

Much of the debate among the bioethicists revolves around the probability that one day humans will not only have access to knowledge of their unborn children's genetic code but will also be able to select and even change certain genetic characteristics of their baby.

(K. Snoddon. Genetics. – WFD NEWS, May 2000. – p.5-6.)