Trying To Figure This Out

When I encountered this article in the British Medical Journal, I was hoping to find some reliable report of the accuracy of the test they mention.  All they do is repeat the manufacturer's claim of 99.9% accuracy.  Then I tried to figure out why this product exists.

BMJ  2005;331:69 (9 July), doi:10.1136/bmj.331.7508.69-c

Home test shows sex of fetus at five weeks of pregnancy
Janice Hopkins Tanne

A finger prick test for pregnant women that can tell them the sex of their child has aroused huge public interest since it was featured on a US television show. The test, which can allegedly show the sex of the fetus at only five weeks of pregnancy, is claimed to be 99.9% accurate...

So there is one question that remains unanswered: how accurate is the test when performed in an uncontrolled setting?  That, however, is not what I am trying to figure out.  Since there is no way to figure it out with the information provided, there is no point in trying.  What I am trying to figure out, is why this thing should be so popular.  The company estimates that 50-70% of parents-to-be want to know if they’re having a baby boy or girl.  Continue reading here.