US Census (Mexican Americans)?

Okay, I hope that this won't confuse you more, but here goes. My husband is Mexican, I'm Black. They clified one of our children as Black, another as Black and White, another as White, and another as Hispanic. I don't know who was responsible for that happening, but it did. We filled out all of the forms the same way, that our childrens' ethnicity was Black, and that thier race was Hispanic. We did it that way because we wanted to make sure they were identified as both. Apparently it only worked with one of our kids. It's so stupid and confusing. I think they must just stick people in whatever slot they need filled!