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Designer Babies: Good Idea or Slippery Slope?

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If there was a technology that could help parents ensure that their kids wouldn’t get cancer or develop genetic diseases, would it be okay to use it? If parents really want a daughter after having four sons, is it wrong to use that technology to select the gender of their next baby? What if you could choose to spare your child the pain and humiliation of acne or obesity? Is it wrong to want your baby to grow up beautiful and tall?


Genetic testing is a very slippery slope. We do have the technology to screen human embryos for specific genetic traits. However, as assisted reproduction grows more sophisticated, it leaves us with extremely difficult ethical questions to consider. While people generally agree that it’s okay to screen embryos for the “undesirable” genes that cause incurable and heartbreaking diseases, the question becomes tougher when we imagine screening babies for attributes like weight, eye color, or intelligence. Soon, science could allow parents to choose the specific physical features of their unborn child. What should we screen for, and when should we allow nature to take its course? What exactly constitutes an “undesirable” gene? Where do we draw the line between disease prevention and engineering designer babies?  


Pre-Screening for Health
The procedure that has everyone concerned is called pre-implantation genetic diagnosis, or PGD. The technique was developed for use with in vitro fertilization to help identify embryos that would be afflicted with deadly or debilitating diseases. In effect, it takes the guesswork out of genetics. After embryos have been fertilized, PGD uses DNA analysis to identify embryos with genetic defects like Down’s syndrome, Tay-Sachs disease, Huntington’s disease, and cystic fibrosis. In fact, there are about 200 diseases and conditions that can be tested for. Parents undergo the genetic testing to make sure that the embryos they choose to transplant don’t have the genes that cause these diseases. Embryos that test positive can be discarded, and the genes eliminated from the gene pool.  


Until recently, the only way to test for genetic diseases before birth was through amniocentesis or chorionic villus sampling, both of which happen farther along in pregnancy. Testing an existing pregnancy is risky, because if a genetic defect is found, the couple would be left with the unpleasant choice of having a disabled child or aborting the pregnancy. PGD prevents couples from having to make that decision, since only healthy embryos are transplanted.


PGD is most often recommended for two types of couples: those with family histories of inheritable diseases, (whose children would be likely to be affected), and older parents. In the case of Huntington’s disease, if one parent is a carrier, the child has a 50 percent chance of inheriting the gene and developing the disease, which is always fatal. PGD seeks to eliminate the disease from the family bloodline and ensures that the child is healthy. The embryos created by older parents may have chromosomal disorders that make miscarriage more likely. PGD can help them by identifying normal healthy embryos, which have the best chances of developing into healthy pregnancies. PGD can be expensive (not to mention the cost of IVF), but the cost is worth it for couples who want to spare their children the agony of a lifelong disease.  


Here Comes the Son
In theory, PGC seems like a miracle, but its real-world applications have proven problematic for medical ethicists. If couples can discard an embryo based on faulty genes, what’s to stop them from discarding based on sex? About 42 percent of fertility clinics that offer PGD do it for the express purpose of allowing couples to choose the sex of their baby. Although the technology isn’t 100 percent foolproof, sex-selective PGD is marketed as a method of “family balancing” in many clinics, allowing families with many sons to select a daughter or vice versa. Some people simply have a sex preference, regardless of their family makeup.


In the U.S., there are no laws against couples choosing the sex of their children, or against sex-selective abortion. In countries such as China and India, though, it’s illegal. Orphanages are already bursting with unwanted baby girls, since their cultures value sons more than daughters, and many couples choose to abort pregnancies once they learn they are carrying girls.


Build-a-Baby Workshop
If scientists are successful in isolating the genes responsible for eye color, hair color, complexion, and intelligence, what’s to stop parents from screening embryos in order to arbitrarily construct their perfect child? Some people feel that PGD techniques are dangerously close to eugenics, since they would allow parents to “breed out” undesirable genes, such as the gene for short stature or dark hair. According to a survey conducted by New York University, 10 percent of respondents would want to screen embryos for athletic prowess, 10 percent would screen for height, and 13 percent would want to choose an embryo that would demonstrate superior intelligence. Even more questionable, some parents with sick children have requested PGD for subsequent pregnancies, so they can be sure that the new child will be able to donate an organ or tissue to its sibling. While it’s true that parents only want the best opportunities for their kids, ethicists worry that this sort of genetic engineering is over the line.


Actually, designing the perfect baby isn’t quite as easy as it sounds. We don’t yet have the technology that can reliably predict physical attributes. Selecting for talent is also more difficult. There isn’t just one gene responsible for traits like athletic aptitude or musical ability. They’re controlled by a host of genes, not to mention that they are partially nurtured by the environment in which a child grows up.


For most scientists, the goal of PGD isn’t to create the perfect baby; it’s to prevent disease. But as with most technology, our abilities have outpaced our understanding of what’s ethical. As much as all parents would love to have beautiful, brilliant kids, some will just have to settle for healthy. Ten fingers and ten toes … perhaps asking for more is pushing it.

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