Is cranial capacity in Rh(D) negative individuals larger?

Why do I think this possible?

• our headshapes
• higher Neanderthal DNA in many of us
• frequency of occipital bun
• self-reported IQ
• IQ potential shown in studies of reaction to Toxoplasma gondii

Cranial capacity: can it indicate high IQ?

Do Rh Negative People have a certain Look?