It's really ironic that they are white twins as well, because Hitler gave them the "privilege" oof being part of science- such things as:

-Having your blood drawn daily.
-Having your genitals removed.
-Having organs--including a stomach or heart--removed without anesthesia.
-Being injected with your twin's blood and visa versa, causing fever and sickness.
-Having your eyes injected with colored dye to see if it eye pigment could be altered, often causing blindness.
-Having your spine severed.
-Being injected with chloroform or phenol along with your twin, causing near instant blood-coagulation to see which one of you died first--or if you would in fact die at the same time.

And when they outlived their usefulness, they were gassed.