This is a slightly tricky one.
I think we all agree on the following:
- There is a claim that microcephaly incidents are currently higher in Brazil.
- There is a popular claim that the Zika virus is the cause.
- There is an alternative claim that pyriproxyfen is the cause.
The real answer might be that Zika is the cause; that pyriproxyfen is the cause; that both are partial causes; that neither are the cause; or even that there has been no increase at all.
(I am not taking any position on the answer. I personally suspect the science isn't really in yet, and we won't have a good answer to this dilemma for months or years, but my opinion doesn't count for much.)
I think the best solution is to have one question that poses all of these questions, rather than several competing questions that will be answered with the exact same evidence. (Normally, I would argue against multiple claims in one question, but these are very closely related - the evidence for one hypothesis is the evidence against another.)
I will merge your question into the other one. There is a substantial answer there already, but I don't think it has satisfactorily addressed the claim yet.