Understanding Designer Children

If you had the choice, would you have preferred to be born with different eye color, hair color, or skin tone? Perhaps you'd have chosen to be taller, thinner, or more athletic. These options were not available to you, as the traits you were born with are largely determined by genetics. But with advancements in genetic research, the possibility of selecting your child's traits, just like customizing a car, might become a reality in the future.

Scientists have just started unlocking the mysteries of the human genome — the genetic code that shapes human beings. The human genome mapping was completed in 2003, and researchers are still working to understand the function of each gene. As of 2010, gene editing in embryos is now a possibility. In 2009, a Los Angeles fertility clinic briefly offered genetic selection of eye and hair color, but had to withdraw it due to public backlash.

The consequences of human genetic manipulation extend beyond simply choosing eye color. In the UK, deaf activists opposed a 2007 law that allowed genetic selection to avoid specific diseases and disabilities, but forbade selecting for them. They argued that deaf parents should have the same right to choose a deaf child as hearing parents have to choose a hearing one [source: TimesOnline].

The same legislation permitted parents to select embryos that could serve as 'savior siblings' — children conceived specifically to be donors for a sick sibling. Some believe that selecting embryos based on tissue compatibility is a form of designer children, much like choosing embryos based on traits like height or hair color.

The concept of designing our children is a reality that governments, ethicists, and religious organizations are just beginning to confront in full force. This article explores the advancements in human genome research, how we are already eliminating genetic diseases, and the future of 'selecting' our children.

At the heart of all potential human genetic manipulation is the human genome — the ultimate goal of genetics research. Scientists completed its mapping in 2003, at least to the extent that current technology allows.

Mapping the Human Genome

Imagine the human body as a vast and intricate encrypted code. The scientists working on mapping the human genome are trying to crack this code. Once decoded, it could unlock numerous secrets about how the body functions and potentially lead to breakthroughs in disease prevention. In June 2000, both the Human Genome Project and Celera Genomics revealed they had assembled a preliminary draft sequence of the human genome, a significant milestone in decoding it.

Researchers are aiming to create a detailed genetic map of the human genome, determining the complete nucleotide sequence of human DNA (deoxyribonucleic acid). Nucleotides are the fundamental units of nucleic acid, which form the 23 pairs of chromosomes in the human body. The Human Genome Project estimates that the human body contains between 26,000 and 40,000 genes. Each gene consists of a distinct sequence of pairs, each containing four bases, known as base pairs.

In the DNA molecule, which resembles a twisted ladder, the bases are the chemicals that form the rungs of the ladder. The sides of the ladder are made up of sugar and phosphate molecules. With around 3 billion base pairs in the human genome, only about 4 percent of these pairs correspond to DNA that influences gene function. The remaining 96 percent of base pairs are still a mystery, often referred to as junk DNA.

The full sequence was completed in 2003, with 99.99 percent accuracy. However, understanding the intricacies of this sequence is still in the early stages of research.

A deeper understanding of the human genome will provide crucial insights into the workings of life itself. This knowledge could pave the way for preventing or curing diseases, as genetics plays a key role in illness — our genes work to combat those of a virus or bacteria. The next step is to decipher how this battle unfolds. Researchers have already identified the locations of some genes responsible for our medical traits. Other genes have been found, though their functions remain unclear, and some are still hidden. The goal of genome research is to pinpoint these genes, understand the sequence of the four bases, and then unravel what these genes actually do…

…which opens up a realm of possibilities.

Genetic Prescreening

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When in vitro fertilization (IVF) was first carried out in 1978, it offered many couples who were otherwise unable to conceive, the chance to have a child of their own. IVF involves extracting eggs from the woman's ovaries, fertilizing them in a lab, and then, after a few days, reintroducing the fertilized egg (zygote) into the uterus. IVF also led to the development of a procedure that enables parents to screen out genetically defective embryos, known as preimplantation genetic diagnosis (PGD).

PGD is frequently used in conjunction with IVF to screen embryos for genetic conditions before they are implanted into the woman's uterus. After the egg is fertilized, a cell is extracted from each embryo and examined under a microscope for indications of genetic disorders. Many couples opt for this procedure if there is a history of inherited conditions in their family, to reduce the risk of passing those conditions to their child. PGD can currently detect a wide range of disorders, including cystic fibrosis, Down syndrome, Tay-Sachs disease, and hemophilia A.

Certain genetic conditions are more prevalent in one gender, like hemophilia, which predominantly affects males. In such cases, doctors may assess the embryos to determine their gender. For families with a history of hemophilia, only female embryos are selected for implantation. This practice has sparked a wider debate about whether parents should have the ability to choose an embryo based solely on gender. Concerns are raised that this could result in a gender imbalance, particularly in societies that have a preference for male children, such as in China.

While PGD allows parents to select embryos free of genetic disorders, and even choose the desired gender, this is just the beginning of what genetic engineering might one day achieve. In the future, parents may be able to custom-select children with specific traits.

The possibility of selecting traits such as hair and eye color is already a highly debated and controversial aspect of genetic engineering.

Exploring the Genetic Options

The concept of altering human genes shouldn’t come as a surprise. Scientists have been modifying the genes of animals for a long time. For instance, goats and cows have been genetically altered to produce more milk or higher levels of proteins in their milk. Mice have been modified with genes linked to Alzheimer’s disease in an attempt to find a cure. In some experiments, jellyfish genes have even been introduced into the genetic makeup of monkeys.

One fascinating example of a transgenic animal is a goat that has had a spider gene inserted into its genome. Spider silk is incredibly strong, and if produced in large quantities, it could create highly durable body armor. While spiders don’t produce enough silk for this purpose, scientists found that spider silk is a protein very similar to one found in goat milk. By adding the spider gene to a goat, it produces a protein identical to the silk protein, which is then harvested from the goat’s milk to create BioSteel fibers, used in bulletproof vests.

Modifying the genetic traits of living animals is now a reality, and some of these animals share genetic similarities with humans. It's a small step from this to creating humans who can jump higher, see farther, hear more acutely (or not at all), or run faster. However, before we can create these enhanced humans, we need to better understand the human genetic blueprint.

One potential method for altering human genetics in the near future is called germline gene therapy. This method extends preimplantation genetic diagnosis by manipulating the genes of reproductive cells – sperm, egg, or early embryos. Unlike simply screening embryos, this approach adds new genes to the cells, potentially allowing almost any trait to be incorporated into an embryo to design a custom child.

Germline gene therapy has already been applied to animals. The genetic modifications in the germinal cells might not manifest in the resulting animal, but could appear in future generations instead.

The long-term effects of germline gene therapy could include the elimination of genetic diseases and disabilities by 'fixing' genetic issues as they arise. However, this could also lead to dystopian scenarios, like a 'Gattaca'-style society where only genetically perfect individuals succeed, or a nation creating superhuman soldiers to dominate the world and enslave others.

In either case, the coming years will likely see heated discussions about the ethical use of genetic discoveries. Will it become standard practice to design children to look, behave, and think in specific ways?