His team has investigated whether synaesthesia is connected to autism. In 1997 Baron-Cohen developed the empathising–systemising theory. His theory is that a cognitive profile with a systemising drive that is stronger than empathising is associated with maths, science and technology skills, and exists in families with autism spectrum disorders. He suspects that if individuals with a "systemising" focus are selecting each other as mates, they are more likely to have children with autism. He postulates that more individuals with autistic traits are marrying each other and having children. He said that "In essence, some geeks may be carriers of genes for autism: in their own life, they do not demonstrate any signs of severe autism, but when they pair up and have kids, their children may get a double dose of autism genes and traits. In this way, assortative mating between technical-minded people might spread autism genes." Baron-Cohen's work in systemising-empathising led him to investigate whether higher levels of fetal testosterone explain the increased prevalence of autism spectrum disorders among males; his theory is known as the "extreme male brain" theory of autism. A review of his book "The Essential Difference" published in "Nature" in 2003 summarises his proposal as: "the male brain is programmed to systemize and the female brain to empathize ... Asperger's syndrome represents the extreme male brain". In 2001 he developed the autism-spectrum quotient, a set of fifty questions that can be used to help determine whether or not an adult exhibits symptoms of autism. The AQ has subsequently been used in hundreds of studies including one study of half a million people, showing robust sex differences and higher scores in those who work in STEM (Science, Technology, Engineering and Mathematics). Baron-Cohen developed the Mindreading software for special education, which was nominated for an award from the British Academy of Film and Television Arts (BAFTA) interactive award in 2002. His lab developed "The Transporters", an animation series designed to teach children with autism to recognise and understand emotions. The series was also nominated for a BAFTA award. Baron-Cohen has faced criticism by some for his "empathizing-systemizing theory", which states that humans may be classified on the basis of their scores along two dimensions (empathizing and systemizing); and that females tend to score higher on the empathizing dimension and males tend to score higher on the systemizing dimension. Columnist at "The Guardian" Madeleine Bunting summarized some of these aspects in the 2010 article "The truth about sex difference is that if men are from Mars, so are women".