A: Reduced or absent brain is caused solely when the neural tube failed to develop into spinal and cerebral tissue from which it's formed.
All you have to do to accomplish this in a developing embryo is to down-regulate folate. This is why women are told to take vitamins when pregnant, these are to avoid birth defects such as these (a sign our standard diet is good enough to prevent death but not actually good enough to reproduce and carry the species forward - that should tell you something) ans this has never been shown to happen because of the Zika virus which is not new and has never caused birth defects in all of history.
However, laboratory tests of pesticide do show is results in the sort of defect seen in those never repeated 7 cases in Brazil where Zika was found a high levels of pesticide were used. One that's known to cause birth defects in the lab.
They stopped using it right away so we probably won't see it again bu the idea they're pushing injections for a disease caused by a pesticide and not what the injection is for is just funny as hell.
If people are going to get their science from politics, why don't we get our politics from scientists then? Fair is fair.