Mayer Eisenstein (January 26, 1946 – December 22, 2014) was an American pediatrician and family physician known for his opposition to vaccines.[1] He was also known for promoting the use of Lupron as a treatment for autism, a practice originally developed by Mark Geier which has been heavily criticized.[2] He founded and ran the Homefirst practice in suburban Chicago in 1973, and ran it until he died in 2014. Homefirst was known for providing physician-attended home births.[3][4] In the 1990s, he attended John Marshall Law School along with his son, Jeremy.[5]