NEW DELHI, India (AP) -- Despite a six-year ban on the use of ultrasound technology to determine the sex of an unborn child, the government said Friday that the practice of aborting female fetuses is still growing.

Data from the 2001 census that showed there are 20 million to 40 million "missing" girls and women in India "came as a rude shock to our consciousness," Deputy Prime Minister Lal K. Advani told a meeting of registrars who record births and deaths.

"This is not only illegal, but is a crime against humanity," he said.

The preference for sons has led to such practices as killing infant girls, although it has been illegal for more than 100 years. The advent of sex determination tests has brought the new practice of aborting female fetuses.

India outlawed prenatal sex-determination tests in 1996 as the ultrasound technology began to spread along with a slide in the numbers of girls born to Indian parents.

But the ban has had a minimal effect. In the 2001 census' count of children 6 or under, there were 927 girls for every 1,000 boys- down from 945 girls in 1991, and 962 in 1981.

Census reports and activists say those numbers mean some 20 million to 40 million girls were aborted or killed in infancy.

Noting that the laws against misuse of the ultrasound technology had been strengthened, Advani said, "If we really care for the girl child, then the effect of this legislation needs to be monitored closely. We need not wait for the next census of 2011 to know whether these distortions have improved of further deteriorated."

Advani said that a plan for a National Register of Citizens, with national identity cards for all of India's 1.05 billion people may help, as no woman would be able to get such tests without identifying herself, and the result of her pregnancy could be tracked.

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