Fox has admitted to going off his medications before presentations.
He did it before Congressional testimony. Whether he did it for this ad is not known, but speculation on that is not out of line.
The most important fact is that the text of the ad is, to put it generously, misleading. Republicans and others don't oppose stem cell research. They oppose use of human embryos and cloned embryos created specifically for use in such research.
The text of the amendment is here.
Looks good enough at the beginning. Where it starts getting cute is when you get to the definitions.
Fox has done similar ads in other political races.