This is something of interest in connection with geo's post about declining birth rates. A new book,
Unnatural Selection: Choosing Boys over Girls and the Consequences of a World Full of Men, delves into the common practice in Asia of using amniocentesis and ultrasound to help assure that more boy than girl babies will be born. The practice also results in lower birthrates, because couples who previously bore only girls would try until they got a boy. Through technology, they now can advance their traditional favoritism by selective abortion of girls. Governments tend not to interfere because slowing population increase is a national goal. If you're interested in reading more, a review can be found at
http://www.washingtonpost.com/mara-hvis ... story.html