Tracking things for no good reason

Could someone explain to me the use of documenting one’s parents ethnic and language groups on a child’s birth certificate is? What possible use can that information be other than for discrimination — either denying something or granting something on the basis of one’s or one’s parent’s ethnic or linguistic group? The only thing I can think is that it could be used for statistics, but that could just as easily come from the census. I think this information is a hold over from when it was used for discrimination, and they just have not removed it, because why would they unless someone forced them to?