Both contemporary medicine and folklore reveal a widespread social desire to attain children of a preferred sex. Discussions of sex selection have been traced as far back as 2000 B.C. in China. Until very recently the only sure way to achieve it was through infanticide. This method was followed in the 1970s with fetal sexing and sex-selective abortion. By the 1990s it became possible to detect the sex of an embryo ex utero and, it is claimed, to sort male- and female-determining sperm. In many cases, sex selection per se is not the primary aim of contemporary reproductive technologies but instead is a necessary or accompanying factor in prenatal diagnosis and the identification of male fetuses or embryos at risk of sex-linked disorders. Worldwide, however, these technologies are increasingly being used to identify, select, and, in some cases, destroy embryos that display no other "defect" than the fact of being female.
The elimination of unwanted females has been and remains widespread. High levels of excess female mortality among infants, children, and adults were found in Europe and European-settled countries well into the nineteenth century and are still found today in less affluent nations. The reverse--widespread killing of males because of a preference for females and general disdain for males--is virtually unknown.
In the past, excess female mortality was often the result of direct killing, whereas today deliberate neglect and overwork usually cause intentional