[bitwize]

I'm white but I put "Prefer not to answer" whenever I'm asked an equal-opportunity question about my race because what difference should it make?

However, at the doctor's office it matters. Black people are at a higher risk for sickle-cell anemia, there's a significant percentage of ethnic Chinese who cannot metabolize alcohol very well, etc. Having your ethnic background on file helps health professionals evaluate your risks for conditions significantly influenced by ethnicity.