I’m not kidding - in modern Russian academic and literary language this term is mostly used in the context of animals, not people.Are you kidding me? that word полукровка is used in the title of many Soviet/Russian books, songs, films..... It is an official term of a child of "two different types of parents"....
Also, in my view, it’s a rude term to use and I’d never call anyone «полукровка».
I still don’t understand what all of this has to do with Russian figure skating