No big thing here.
According to the census, the 16 mile area where I live and work is the most ethnically diverse area in the country.
It surprised me to know that seeing as how I always figured it would be New York City or somewhere else.
As a result though, you tend to see mixed race kids as a matter of routine.
Incidentally, mixed race adults, women particularly, are IMO somehow more attractive than their 'pure blooded' counterparts.