Autistic people have different talents and challenges to neurotypical people. Many autistic people can experience challenges concerning sensory issues, social communication and interaction and they can express a preference for repetitive patterns of behaviour, and have focused interests. Autism can be diagnosed at any age but typically signs of autism appear in the first two years of life. Autism is regarded as occurring on a spectrum because there is a wide variation in the type and severity of the challenges that autistic people experience.  One in fifty-nine children worldwide are autistic. Four boys are diagnosed to every girl.  There is a 35-fold increase in prevalence in autism since the earliest studies were conducted in the late 1960s. Research suggests that autism is caused by a combination of genetic and environmental influences.