Chinese, Korean and Indian families in America appear to be using sex-selection techniques — including abortions based on gender — to maximize the odds of having boys, reports The New York Times:

In those families, if the first child was a girl, it was more likely that a second child would be a boy, according to recent studies of census data. If the first two children were girls, it was even more likely that a third child would be male.
Demographers say the statistical deviation among Asian-American families is significant, and they believe it reflects not only a preference for male children, but a growing tendency for these families to embrace sex-selection techniques, like in vitro fertilization and sperm sorting, or abortion….
Dr. Lisa Eng, a Hong Kong-born gynecologist who practices in Chinatown and Sunset Park, Brooklyn, said she tried to discourage couples who prefer boys from having abortions.
But, she said, “If it’s going to be a third, they’re pretty determined to have a boy. If it’s a boy, they keep it. If it’s a girl, they’ll abort.”