Percent of 3- to 21-Year Old Children with Special Educational Needs (Compared to Total Public School Enrollment) Nature or Nurture Communities have always has some children with special needs, with physical, emotional, and neurological disorders of many kinds. In some eras, and even today in some nations, the education of such children was neglected. Indeed, many children were excluded from normal life even before they quit trying. Now in the United States every child is entitled to school. As you see, the specific label for such children has changed over the past decades, probably because of nurture, not nature. Thus teratogens before and after birth, coupled with changing parental and community practice, probably caused the rise in autism and developmental delay, the decrease in intellectual disability, and the fluctuation in learning disabilities apparent here.

Source: U.S. Department of Education.