Image copyright Other Image caption Today, 112 boys are born for every 100 girls in India, against the natural sex ratio at birth of 105 boys for every 100 girls

Did the West stoke the scourge of sex selection in Asia?

A strong socio-cultural preference for boys in conservative Asian societies is blamed for most of the sex selection. In overwhelmingly patriarchal India, dowry makes daughters expensive. China's one-child policy is thought to be a trigger as women abort girls to have a single boy.

But the story of sex selection in Asia is not as simple as it looks from the outside, writes award-winning science journalist Mara Hvistendahl in her startling new book Unnatural Selection.

Hvistendahl points a finger at the West for encouraging the epidemic of sex selection which has gripped Asia since the early 1970s.

Amniocentesis tests and ultrasound scans have led to more than 160 million girls being aborted in Asia alone since then, according to one widely quoted 2005 estimate.

It had to do, Hvistendahl writes, with the West's paranoid population control movement during the Cold War - a growing fear that more hungry babies would grow up and turn to communism. The "monster of sex determination in Asia" lead to vastly skewed ratios in countries like India, China and South Korea.

Western money, she writes, was used to set up an extensive network of family planning advisers and doctors that encouraged women to opt for amniocentesis.

That's not all. Throughout the late 1960s and early 70s, writes Hvistendahl, influential US experts supported sex selection in academic papers and government-sponsored seminars - "a disturbed sort of technological sexism".

In 1969, sex determination was included as one of the 12 new strategies for global birth control at a US workshop. Henry Kissinger, then secretary of state under Richard Nixon, signed a classified memo stating that "abortion is vital to the solution" of population growth in the world.

So in India, Hvistendahl says, advisers from the World Bank and other organisations pressured the government to "adapt a paradigm" where population was the problem. The Rockefeller Foundation and the Ford Foundation poured money into "research into reproductive biology".

And in the mid-1960s, she writes, leading American embryologist and biochemist, Sheldon Segal, showed doctors at India's top medical school AIIMS, how to test human cells for sex chromatins that indicate whether a person is female - a method, she says, that was the precursor to foetal sex determination.

In India, the early sex selective abortions were performed openly at government hospitals. Doctors helped identify the sex and abort the foetus if it was a girl. Hvistendahl quotes from papers written by senior doctors belonging to India's premier medical school, the All India Institute of Medical Sciences (AIIMS), in which they back prenatal sex determination as a way of putting an end to "unnecessary fecundity". In other words, female foetuses were aborted in the name of population control.

It was only in the late 1970s, when India's feminist groups and other campaigners began making a noise about sex selection, that the authorities took notice.

By that time, writes Hvistendahl, the damage had been done. At AIIMS alone, doctors had aborted an estimated 100,000 female foetuses. Taxpayers' money and Western funding had been spent to fund sex selective abortions. Today, 112 boys are born for every 100 girls in India, against the natural sex ratio at birth of 105 boys for every 100 girls. This is what Dr Sabu George, a leading expert on sex selection, calls the "forgotten story" of India's missing girls.