marry out, marry in

アメリカで異人種間の結婚率が建国以来、過去最高に達したとのニュースです。married in、married outという言い方も珍しくなくなるかもしれません。UG先生から以前、endogamy/exogamyという表現を教えていただいたことを思いだします。（GP）
The Rise of Intermarriage
Rates, Characteristics Vary by Race and Gender
February 16, 2012

Marriage across racial and ethnic lines continues to be on the rise in the United States. The share of new marriages between spouses of a different race or ethnicity increased to 15.1 % in 2010, and the share of all current marriages that are either interracial or interethnic has reached an all-time high of 8.4%.

In 1980, just 3% of all marriages and less than 7% of all new marriages were across racial or ethnic lines. Both of those shares have more than doubled in the past three decades.

While newlyweds who "married out" between 2008 and 2010 are very similar to those who "married in," judging by characteristics such as education, income and age, there are sharper differences among them based on the race, ethnicity and gender partnerships of the couples.

Just as intermarriage has become more common, public attitudes have become more accepting. More than four-in-ten (43%) Americans say that more people of different races marrying each other has been a change for the better in our society, while only about one-in-ten think it is a change for the worse.

http://pewresearch.org/pubs/2197/intermarriage-race-ethnicity-asians-whites-hispanics-blacks