Beginning with Amartya Sen's demographic calculations in the Eighties, estimates of how many women die each year in excess of demographic projections have been gradually refined.

The term "missing women" was coined in 1990, when Indian economist Amartya Sen calculated a shocking figure. In parts of Asia and Africa, he wrote in The New York Review of Books, 100 million women who should be alive are not, because of unequal access to medical care, food and social services. These are excess deaths: women "missing" above and beyond natural mortality rates, compared to their male counterparts.

His research began a flutter of activity in academic circles and by 2005, the United Nations produced a much higher estimate for how many women could be "missing": 200 million.

(Details of various methodolgies for estimating the number of "missing women" are discussed in The Elgar Companion to Development Studies, which is available online, beginning at page 389.)

Professor Siwan Anderson of the University of British Columbia is one of the principle researchers whose work supports the recent UN estimate 200 million "missing women," and some of her conclusions are very dark.

In China, Anderson says, most of the 141,000 excess female deaths by injury were suicides, making China the only place in the world where women are more likely than men to kill themselves, often by eating pesticides used for crops.

    And in India, a category called "injuries" yielded ominously high figures: 86,000 excess deaths in the age group 15-29 in 2000 alone. Anderson has done extensive research in India, and says the numbers beg the question of exactly how many deaths were so-called "kitchen fires" - often used to mask dowry-related killings, the result of a new bride being tortured by her new family until her parents pay their debts.