At birth, there is a slight bias towards males born. However that is something in the order of 51% male babies to 49% female babies. That is far less pronounced than what is being observed.
That's not too far off from the figures quoted in the article – a 2% difference of 1.4 billion (China's population) would be 28 million, which is not too much less than the 34 million difference quoted in the article.