Asian mom, German dad or vice versa.
I had pretty Japanese female student in one of my design classes at Pitt State in Kansas in the 80s. I noticed one day that she had hair on her forearms and I asked her if she was part Mongolian or Ainu, not in front of the class though. She told me that her grandmother was German, ergo hair on the forearms. I paid a lot of attention to pretty Asian girls in my much misspent youth. Actually I wasn't prejudice at all. I paid attention to pretty girls of all races and nationalities.
Mongolians have a lot more body hair than other Asians so do Japanese Ainu for those that give a $hit.