Why did I never hear this in Korea?

This (courtesy of Slate) is the kind of factoid I came to expect in Korea:

[K]ids adopted from Korea outscored the U.S. average by two to 12 points, depending on their degree of malnutrition. In a third study, Korean kids adopted in Belgium outscored the Belgian average by at least 10 points, regardless of their adoptive parents' socioeconomic status.

Go read the whole unflinching article.