That's why I like the "make it illegal to even ask"-type of policy. At some of these American firms they asked me things like my sexual orientation and religion, aspects you often can't infer from appearance, and that always seemed rather odd to me – I'll just have to trust it won't be used to discriminate. If I don't tell this information I
know they can't.
Things like age, gender, and ethnic group are harder because you can't always conceal that. Still, "don't ask, don't tell" during the hiring process seems like the best option here.