Sir Simon Philip Baron-Cohen (born 15 August 1958) is a British clinical psychologist and professor of developmental psychopathology at the University of Cambridge. He is the director of the university's Autism Research Centre and a Fellow of Trinity College. In 1985, Baron-Cohen formulated the mindblindness theory of autism, the evidence for which he collated and published in 1995. In 1997, he formulated the prenatal sex steroid theory of autism, the key test of which was published in 2015. In 2003, he formulated the empathising-systemising (E-S) theory of autism and typical sex differences, the key test of which was published in 2018. He has also made major contributions to research on autism prevalence and screening, autism genetics, autism neuroimaging, autism and vulnerability, autism intervention and synaesthesia. Baron-Cohen was knighted in the 2021 New Year Honours for services to people with autism. In 2023, he was awarded the Medical Research Council (MRC) Millennium Medal.