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% to 75% male children. Currently, approximately 50 gender selection centers in the United States use