According to the authors, these are mostly children of interracial couples that aren’t writing down their diverse heritages. Mixed marriages are increasingly common in America — Pew finds that about 26 percent of Hispanics marry a non-Hispanic these days, and 28 percent of Asians marry a non-Asian. To accommodate this trend, government surveys now allow you to check multiple boxes for your race and ethnicity.

But it turns out that many aren’t doing that.

The report from Duncan and Trejo has two major consequences. First, it casts some doubt on the government’s projections of the future Hispanic and Asian populations. Famously, the Census Bureau has predicted that non-Hispanic whites will become outnumbered in America by as early as 2044. But as Pew has pointed out, these calculations don’t take into account trends in how the children of mixed marriages report their own race. A fair fraction of people with Asian or Hispanic heritage actually consider themselves exclusively white (or black).

Second, the report may cause us to reconsider what we think we know about Hispanics and Asians.