What's the problem? Even under the narrowest definitions, there were tens of millions of Aryans at the time. They could easily have only married each other without genetic deformities.
I was thinking the same thing. It seems the Nazis (at least originally) put as much of an emphasis on
Germanic heritage as they did
German speakers. In other words, a lot of Nazis would absolutely consider Danes or Swedes Aryan. Once you count up the populations of Germany, Denmark, Austria, Sweden, Norway, Iceland, the UK and the Netherlands (even if only certain portions "counted" to them), you more or less have "Northern Europe." No one thinks all of Northern Europe would inbreed itself, LOL.
