Israel) and is in line with the finding that mothers of autistic children themselves have elevated sex steroid hormones. But to really test the theory Baron-Cohen needed a much larger sample than his Cambridge Child Development Project, since autism only occurs in 1% of the population. So, in 2015, he set up a collaboration with the Danish Biobank which has stored over 20 thousand amniotic fluid samples which he linked to later diagnosis of autism via the Danish Psychiatric Register. He tested the prenatal androgens and found that children later diagnosed as autistic were exposed to elevated levels of prenatal testosterone, and the Δ4 sex steroid precursors to prenatal testosterone. In 2019 he tested the same cohort's levels of exposure to prenatal estrogens and again found these were elevated in pregnancies that resulted in autism. These novel studies provide evidence of the role of prenatal hormones, interacting with genetic predisposition, in the cause of autism. Developmental social cognitive neuroscience While a member of the Cognitive Development Unit (CDU) in London in 1985, to explain the social-communication deficits in autism, Baron-Cohen and his colleagues Frith and Alan Leslie formulated the "theory of mind" (ToM) hypothesis. ToM (also known as "cognitive empathy") is the brain's partially innate mechanism for rapidly making sense of social behavior by effortlessly attributing mental states to others, enabling behavioral prediction and social communication skills. They confirmed this using the false belief test, showing that a typical four-year-old child can infer another person's belief that is different to their own, while autistic children on average are impaired in this ability. Baron-Cohen's 1995 book Mindblindness summarized his subsequent experiments in ToM and its impairment in autism. He went on to show that children with autism are blind to the mentalistic significance of the eyes and show deficits in advanced ToM, measured by the "reading the mind in the eyes test" (or "eyes test") that he designed. He conducted the first neuroimaging study of ToM in typical and autistic adults, and studied patients demonstrating lesions in the orbito- and medial-prefrontal cortex and amygdala can impair ToM. He also reported the first evidence of atypical amygdala function in autism during ToM. In 2017, his team studied 80K genotyped individuals who took the eyes test. He found SNPs partly contribute to individual differences on this dimensional trait measure on which autistic people are impaired. This is evidence that cognitive empathy/ToM is partly