The Censorship of Bias

From Best of the Web, a report on something every woman has the right to choose but must not be called by name:

The New York Times reports that South Korean men are increasingly marrying
mail-order brides from Vietnam:

More and more South Korean men are finding wives outside
of South Korea, where a surplus of bachelors, a lack of marriageable Korean
partners and the rising social status of women have combined to shrink the
domestic market for the marriage-minded male. Bachelors in China, India and
other Asian nations, where the traditional preference for sons has created a
disproportionate number of men now fighting over a smaller pool of women, are
facing the same problem.

The rising status of women in the United States sent
American men who were searching for more traditional wives to Russia in the
1990s. But the United States' more balanced population has not led to the
shortage of potential brides and the thriving international marriage industry
found in South Korea.

How exactly has "the traditional preference for sons . . .
created a disproportionate number of men"? Traditionally, after all, a couple
having a baby didn't get to choose its sex. Do South Koreans engage in
sex-selective abortion or infanticide in order to realize their "traditional
preference"? The Times is too delicate to say.