Sex selection is the attempt to control the sex of the offspring to achieve a desired sex. It can be accomplished in several ways, both pre- and post-implantation of an embryo, as well as at childbirth. It has been marketed under the title family balancing.
According to the United Nations Population Fund, the reasons behind sex selection are due to three factors and provide an understanding for sex ratio imbalances as well as to project future trends. These factors are:
A preference for sons which stems from household structures "in which girls and women have a marginal social, economic and symbolic position, and consequently enjoy fewer rights." These household structures also focus on security in which sons are expected to provide support to their parents throughout their life; Technological growth of prenatal diagnosis which allows parents to know the sex of their unborn child; and Low fertility which increases the need for sex selection by reducing the probability of having a daughter in smaller families.
The United Nations Population Fund states that "Local fertility restrictions and spontaneous rapid fertility decline below replacement levels tend to compel parents who want both a son and a small family size to resort to sex selection."
Preference for sex of child
In many cultures, male offspring are desired in order to inherit property, carry on the family name and to provide support for parents in old age.
In countries such as India, China, Indonesia and Nepal sons have been favored over daughters. According to a 2018 Gallup poll, American parents favor boys by a 36% to 28% margin. The results were similar to a survey in 1941, when Americans preferred a boy to a girl by a 38% to 24% margin. The overall preference was driven by men, of whom 43% preferred a son compared to 24% who preferred a daughter. Men's preference for sons was most pronounced among men aged 18 to 29. Women, on the other hand, showed no preference for either sex, with 31% stating that they preferred a girl and 30% responding that they favored a boy.
A 2009 study at the University of Ulster found that having sisters, as compared to brothers, can enhance the quality of an adult's life.
Cultural son preference
There is a preference of parents to have a son over a daughter in many countries. This can be observed through sex ratios of children in various countries. Although biologically the sex ratio of children is around 95 girls to every 100 boys, this number generally evens out due to the higher infant mortality rate of boy infants. Scholars argue that the expected birth sex ratio in a normal population is in the range of 103 to 107 males to females at birth. However, in a number of countries of South Asia, East Asia and the Caucasus, the sex ratio of children is severely distorted. The problem is particularly severe in China and India. The preference for sons over daughters can be connected to a number of reasons. In these countries, it is argued that son preference is linked to factors including economics, religion, and culture. Having a son ensures that families are more economically secure by not having to provide dowry payments, but rather being on the receiving end of this practice. In China, the one child policy has contributed to the sex imbalance, while the dowry system in India is responsible for a strong son preference. Furthermore, in countries where there are discriminatory practices regarding women inheriting, owning, or controlling land by law, having a son ensures that the family will not have to worry about the legal aftermath if something were to happen to them. It can also be argued that parents in these countries are aware of the potential hardship their daughter would have to endure in her lifetime, and therefore prefer to have a son in order not to see their daughter endure such difficulties. Many times this son preference results in female foeticide and pre-natal sex selection.
Methods
Pre-implantation
Two major types of pre-implantation methods can be used for social sex selection. Both of them are based on actively rendering the second sex chromosome to be either a Y chromosome (resulting in a male), or an X chromosome (resulting in a female).
The Ericsson method
The Ericsson method, first applied in a clinical setting in the 1970s by Dr. Ronald J. Ericsson, uses higher concentrations of sperm of the desired sex to increase the likelihood of conceiving that sex.
When used to increase the likelihood of a female child, studies have resulted in between 70% and 80% female children.
When used to increase the likelihood of a male child, studies have resulted in between 50% and 75% male children.