Sex selection
Sex selection refers to the use of medical technology to determine and choose the sex of a future child, typically prior to fertilization or embryo implantation. The two main techniques utilized are sperm sorting and pre-implantation genetic diagnosis (PGD). Sperm sorting separates X and Y chromosome-bearing sperm, allowing parents to select the desired gender before fertilization. On the other hand, PGD involves fertilizing eggs in a lab, testing embryos for their sex, and then implanting only those of the preferred gender, which has raised significant ethical concerns.
While some parents opt for sex selection for medical reasons—such as a family history of sex-linked genetic conditions—others might do so due to cultural preferences or personal desires, such as family balancing. This practice, particularly in countries with a strong preference for one gender, has sparked discussions about its implications on gender ratios and societal norms. Critics express concerns that sex selection could lead to a societal trend towards "designer children," where physical traits are chosen based on parental preferences, potentially exacerbating inequalities based on access to such technologies. The legality of sex selection varies globally, with several countries banning practices like PGD due to these ethical dilemmas and societal impacts.
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Sex selection
Sex selection involves using medical technology to choose whether a future child is male or female. Several procedures allow parents to choose a child's sex before fertilization or at the time an embryo is implanted. These procedures can be helpful in cases in which a family has a genetic health condition that is related to gender. However, experts have also identified a number of practical and ethical concerns associated with sex selection when done for purposes of parental preference. These include placing unfair expectations on a child of a chosen gender and altering the balance of males and females in a given country. There is also concern that sex selection can become a step toward "designer children," in which parents choose physical characteristics such as hair and eye color of their children.
Background
Medical technology has been able to identify the sex of fetuses since the 1970s. Medical procedures such as amniocentesis, in which some of the fluid surrounding the fetus is drawn out with a needle and tested to reveal certain characteristics of the developing child, and ultrasound imaging, in which sound waves are used to create an image of the baby growing inside the mother, have been used to determine the sex of unborn children.
In the 1990s, in vitro fertilization (IVF) techniques were developed that provided an opportunity for parents to choose the child's sex before conception, which is the point at which the male sperm fertilizes the female egg. IVF fertilizes the mother's egg through one of several medical procedures rather than through sexual intercourse. The physician could either introduce the sperm to the woman's reproductive tract through a tube, or extract both eggs and sperm from the parents and place them in a petri dish together for fertilization. The fertilized eggs are then implanted in the mother's uterus.
Sperm and eggs both contain chromosomes, the part of DNA that determines a person's genetic makeup. Males have X and Y chromosomes in each cell, while females have two X chromosomes. When an egg is fertilized, each parent contributes one chromosome to the genetic makeup of the future child. Since the mother has two X chromosomes, the father's chromosomes determine whether the child is male or female. If the sperm that fertilizes an egg contains a Y chromosome, the child will be male, while an X chromosome will result in a female child.
Beginning in the 1990s, physicians found ways to influence the child's sex. They either pre-chose sperm to create the desired gender before the egg was fertilized, or fertilized the egg and then chose embryos of the desired gender to implant in the mother. This technology made it possible for parents to select the sex of their future child or children.
Overview
Parents consider sex selection for a number of reasons. Some choose it for medical purposes because of a family history of serious illnesses that are passed down genetically to children of a specific gender. For example, Duchenne muscular dystrophy and hemophilia are two diseases that are more common in males than females, and hydrocephalus, or life-threatening cerebrospinal fluid on the brain, is known to be linked to the X chromosomes in some families.
In other cases, the reasons are cultural or personal. For instance, in some countries such as China and India, there is a strong cultural preference for boys. In other instances, the reason is that one or both parents prefer a child of a particular gender. This can be because of what gender selection service providers call "family balancing," in which a family already includes one or more children of one gender and wants to balance this with a child of the opposite sex.
There are several techniques used for sex selection. One option is sperm separation, in which a sample of the father's sperm is placed into a machine called a centrifuge. X chromosomes are longer and heavier than Y chromosomes, so sperm carrying female X chromosomes are heavier than those with Y chromosomes. This weight difference allows the centrifuge to separate the X sperm from the Y sperm. The physician then introduces the sperm for the desired gender to the egg, either in a test tube or inside the mother.
The sperm-sorting process was first used in 1995. Other methods of sperm sorting include flow cytometry, which uses laser or other technology to examine cells suspended in a fluid, or by adding chemical coloring or stain to the sperm to help identify sperm for the desired sex of the fetus. Sex selection providers claim as high as a 91 percent success rate in producing a child of the desired gender.
The sperm-sorting process raises some ethical questions, but it is not as controversial as a post-conception selection process called PGD, or pre-implantation genetic diagnosis. The technique was originally developed to help identify embryos with serious genetic diseases such as cystic fibrosis and Tay-Sachs disease, but was later put to use for sex selection. In this process, the physician combines the sperm and egg in a test tube and allows embryos to develop. When the embryos reach eight cells in size, one cell is extracted and tested to determine its chromosomal makeup. The physician then implants only those embryos that are identified as being of the desired sex.
This procedure is controversial because many of the people who undergo this expensive and invasive procedure do not have fertility issues that would necessitate IVF. Sex selection opponents say this presents an unnecessary medical risk. The process also usually creates more embryos than are needed for the IVF process, which raises ethical questions of what to do with the extra embryos.
Sex selection with PGD raises the ethical concern of skewing gender populations if too many parents choose children of one sex. Medical ethicists are also concerned that PGD is moving medical science closer to promoting the elective choice of other characteristics of children such as eye and hair color. Others feel it could create significant class differences, as those who can afford it may genetically engineer children to be free of many diseases while those without financial means will suffer from genetic-based health conditions. Because of these concerns and others, sex selection technologies such as PGD are illegal in many countries, including Australia, Canada, China, India, and the United Kingdom.
Sex selection also carries certain medical risks. IVF carries several risks, including Ovarian Hyperstimulation Syndrome (OHSS), which occurs when the ovaries overreact to the administered fertility medications. The overreaction causes the accumulation of excessive fluid and swelling and can be mild to life-threatening. The risks of sperm sorting are still being discovered and more research is necessary to understand the risks these procedures pose fully. Some studies have concluded that the Hoechst dye used can have a mutagenic effect on the sperm, which can increase the risk of birth defects and genetic disorders in offspring. Like with any medical procedure, patients should be well informed and understand the risks.
Bibliography
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