What more need a libertarian say about this issue? Gillespie and Welch disagree. They praise Tiger Woods for calling himself a "'Cablinasian', a neologism that combined his various racial and ethnic components. Weren't we -- finally -- at a point in history where everyone was ready to move on from simple, either-or categories?...As a Cablinasian he [Woods] represents something that's in all of us." (pp.130, 140) Why is mixing categories a libertarian issue? Here's why: Intermarriage and mixing -- of people, of categories, of ideas -- leads directly to more pluralism, more trade, more possibilities, and fewer opportunities for the majority to inflict its preferences onto less desirable minorities by force and exclusion. Here's how we make that case in the book: With variety -- of ethnicities, of genders, of races, of clothing, of food, and more -- comes mixing. The percentage of foreign-born residents in the United States is about 12.5 percent, according to the Census Bureau, up from just 4.7 percent in 1970. Not coincidentally, Pew Research reports that one in seven marriages is now interracial or interethnic, an all-time high. While such couplings remain a small fraction, the trend captures an undeniable reality that has been gaining ground for the past few decades. "In 1961," write Pew's Jeffrey S. Passel, Wendy Wang, and Paul Taylor, "the year Barack Obama's parents were married, less than one in 1,000 new marriages in the United States was, like theirs, the pairing of a black person and a white person, according