Google, Microsoft, and Yahoo have been showing search ads in India that promote pre-natal sex selection in violation of Indian law, a public interest lawsuit charges.

Google India, Yahoo India, and Microsoft have been asked by India's Supreme Court to respond to a complaint filed by Dr. Sabu Mathew George, whose petition claims that the three companies have failed to follow India's Preconception and Prenatal Diagnostic Techniques Act (1994).

The Act aims to prevent "the misuse of [pre-natal diagnostic] techniques for the purpose of pre-natal sex determination leading to female feticide." In India, as in other countries, female children are often valued less than male children, a tradition that prompts some parents to terminate pregnancies that would result in the birth of a female infant.

George is seeking to block access to Web sites that violate the Act, according to India's The Hindu.

According to a 2006 report in British medical journal Lancet, 10 million female fetuses have been aborted in the past two decades in India. The Guardian in the U.K. reports that Indian parents abort half a million female fetuses a year. The site Maps of India shows the sex ratios in different regions of India as of 2001, based on census data.

Google and Yahoo did not immediately respond to a request for comment. But both companies appear to have taken some action -- at least in India. A search for "sex selection" on Google India returns no text ads, in contrast to 63 sponsored links for the same keywords at Google.com. Yahoo India likewise returns no sponsored results for those keywords. A Microsoft Live Search conducted through MSN India returned two search ads offering information about gender selection.

Google's ad policies ban the promotion of specific illegal or controversial activities, such as the promotion of hacking and cracking sites, but the company does not have a blanket prohibition on the promotion of illegal activities.

Google does ban ads that promote violence or advocate against a protected group, a definition that could be stretched to accommodate pre-natal sex selection ads as a form of gender violence. However, since such ads generally offer information, without explicitly suggesting how that information might be used, banning them would curtail the availability of information about socially acceptable uses of pre-natal screening.

In any event, all three search engines return organic links to Web sites with information about gender selection. So searchers will still be able to find out about pre-natal screening technology and techniques. The information just won't be sponsored.