The biologically normal sex ratio at birth ranges from 102 to 106 males per 100 females. However, ratios higher than normal – sometimes as high as 130 – have been observed. This is now causing increasing concern in some South Asian, East Asian and Central Asian countries.

The tradition of patrilineal inheritance in many societies coupled with a reliance on boys to provide economic support, to ensure security in old age and to perform death rites are part of a set of social norms that place greater value on sons than daughters. In addition, a general trend towards declining family size, occasionally fostered by stringent policies restricting the number of children people are allowed to have, is reinforcing a deeply rooted preference for male offspring. As a result, women are often under immense family and societal pressure to produce sons. Failure to do so may lead to consequences that include violence, rejection by the marital family or even death. Women may have to continue becoming pregnant until a boy is born, thus putting their health and their life at risk.

Sex selection can take place before a pregnancy is established, during pregnancy through prenatal sex detection and selective abortion, or following birth through infanticide or child neglect. Sex selection is sometimes used for family balancing purposes but far more typically occurs because of a systematic preference for boys. Although the relatively recent availability of technologies for the early determination of sex has provided an additional method for sex selection, this is not the root cause of the problem. Where the underlying context of son preference does not exist, the availability of techniques to determine sex does not necessarily lead to their use for sex selection.

This resource is also available at:

http://whqlibdoc.who.int/publications/2011/9789241501460_eng.pdf

http://www.un.org/apps/news/story.asp?NewsID=38711&Cr=gender+discrimination&C