I mean, this kind of shit was inevitable, when you have Pennsylvanian Dutch (Germanics) mixing with east coast Anglos mixing with the south (Ulser-Scots) mixing with the Minnesota-Wisconsin region (Scandinavian) mixing with Louisiana (Franks) mixing with the upper-east coast (Irish and Italians) mix- it just goes on and on and on.
If constant ethnic mixing exists in the States, the next logical step is race mixing.