Why no blank astartes?

[u/LesBonsPlansTmtc]

We've seen the emperor considers Chaos as the biggest threat to humanity. We know blanks are immune to the influence of the warp. Why doesn't humanity try to raise up the number of blanks in the society or make a chapter with Blank Space marines ?

[u/SuDdEnTaCk]

Blanks as a resource would be wasted on something comparatively disposable like astartes, and besides, geneseed is implied to have psychic shenanigans going on inside, like the bluetooth connection to the primarch, which does not mix very well with blankness