Because any prenatal sex determination (even by ultrasound) is illegal in India, due to the unbalanced sex ratio caused by aborting baby girls, India's Supreme Court has been petitioned to block the Baby Gender Mentor web site. BGM is a DNA test which claims to be able to determine an unborn baby's gender at just 6 weeks of pregnancy with 99.9% accuracy; but was found to be very inaccurate and the company was sued in a class-action lawsuit. For a while the test was taken off the market, but may be available again. And apparently, after a deluge of bad press in the U.S., BGM has been advertising in Indian newspapers.
http://www.ptinews.com/pti%5Cptisite.nsf/0/47489987555C6C9E6525748D004C5A01?OpenDocument
Unfortunately, this petition and press coverage of it probably work to BGM's advantage, because they seem to legitimize the test. Not only do more people hear about the test, they assume the test works if the government takes steps to ban it or if there is discussion about whether the test is ethical.
To date, India has been completely unable to enforce its laws against prenatal sex determination and sex selective abortion; there will be no difference here, people will just find a way to get the test illegally. After all the test is mainly just a piece of special paper for collecting a blood spot; it doesn't have to be in a bright orange box, it could come in a plain white envelope.
And the people who get it will likely make a life-or-death decision based on inaccurate information.