Evelyn Johnson Chapman (1935-2016) and John Hume Chapman (d. 2000) married in 1959 and had three children. Their oldest son, Coolidge, was born with brain damage which caused physical and mental developmental disabilities. Unable to enroll him in Seattle Public Schools for kindergarten, they placed him in an experimental program at the recently formed Northwest Center for the Retarded (now the Northwest Center) in 1966. The Chapmans and other parents of children with disabilities became deeply involved in the Center, working to raise city and state support for its programs, with the eventual goal of obtaining public funding for their children's educations. John Chapman, an attorney, served on the Board of Trustees of the NCR and was Board President in 1969-1970. Evelyn Chapman led a group of four mothers and two University of Washington law students on the Northwest Center Legislative Committee fighting for "Education for All" legislation in Washington state. Washington State House Bill 90 was passed in 1971, mandating public education for children with disabilities. The bill went into effect in 1973 and became the basis for the Federal Education of All Handicapped Children Act of 1975 (Public Law 94-142). Coolidge Chapman began attending Seattle Public Schools in 1973 and graduated from Franklin High School in 1983. Evelyn Chapman went on to work for the City of Seattle for over 30 years, and was involved programs for women and children, immigrant families, and people with disabilities.

On May 29, 1968, Evelyn Chapman, chairman of the Northwest Center Legislative Committee, gave a speech in front of King County legislators. She describes the ideal school for developmentally disabled children, and notes that the Northwest Center is the only educational facility in Seattle for these children, who would otherwise be in institutions or at home. She asks legislators to help by providing more funding for early education, teacher training, and building improvements.

In this speech, Evelyn Chapman uses various forms of the word "retarded," which was in common use in the 1960s, and preferable at the time to pejorative terms for cognitively disabled people used previously. Today, the preference is to describe an individual as having a particular disability rather than being defined by it, by using descriptions such as "children with developmental disabilities."