Sex ratio at birth among Chinese babies born in Italy is lower than in China.

I n industrial countries sex ratio at birth (SRB) (male/ female) varies between 1.07 and 1.03, with a decreasing trend in the past few decades. Population statistics of the past 20 years report that SRB in China is constantly and considerably increasing. According to official census data, the SRB of Chinese newborn babies was 1.168 in 2000 but in some provinces it exceeded 1.3. The increase of SRB has been a cause of concern in China as it is considered a possible cause of relevant social problems for the future, because of the increasing surplus of adult men without a female partner. As no data are currently available about the SRB among Chinese living outside their homeland, we decided to calculate the SRB of an entire population of live births born during a decade to ethnic Chinese people settled abroad.