The female population has been declining is some areas because of preference for the male. In India, the sex ratio in 1983 was 935 females to a 1,000 males, in 1985 in Korea Rep there were 110.4 males to 100 females, in 1989 some parts of China had a ratio of 121 males to 100 females. The chances that female population will drop even further have been increased with the possibility of sex-determination and abortion.
Dealing with the cultural devaluation of girls by preventing their birth is a gross capitulation to sexism. Instead, China, India and other countries must fight the attitudes and traditional values that lead to the undervaluing of daughters.
Pre-natal sex testing is partly a solution to overpopulation. It limits the size of of a family in a scientific way. Women may stop having children once they have had their son. And with less girls, less children will be born.