One word: vaccines.

McCarthy has long been an outspoken opponent of vaccinating children, claiming that her 11-year-old son’s diagnosis with autism in 2005 was due to his baby vaccinations.

“Jenny has used her celebrity status to publicize medical claims that have not been proven by the literature. While it is understandable that she has her own views on immunizations given her child, she is going to be in front of impressionable young mothers and influencing their decision on immunizations and child care. Multiple studies have shown that there is no link between childhood immunizations and autism, but she continues to publicize the grave ‘dangers’ of vaccinations,” Dr. Shilpi Agarwal M.D., board-certified family physician told FOX411’s Pop Tarts column.  “While Jenny cannot deliver direct medical advice, she is definitely influencing many young mothers as to what is ‘right’ and ‘wrong’ in terms of child care and immunizations. I suspect she will get a lot of pushback, which may be exactly what a show like ‘The View’ wants."