From 1927 to 2009, Ontario implemented and maintained a “closed” adoption system. In this system, when a first parent surrenders a child for adoption, the laws state that the child's original Statement of Live Birth must be placed in a sealed record along with any information that might identify the child's first family. Under no condition will these records be turned over to the adoptee. When the child is adopted, the adoptive parents create a new Statement of Live Birth replacing the first parents' information with their own. Essentially, the child is permanently cut off from his/her family and heritage. At no time after the adoption is finalized, can the first parents rescind their decision; at no time may they seek access to the child's new identifying information.

Since the 1970s, many adoptees, now adults, began to vocalize their need to establish ties with their first families. From this need grew the adoption reunion movement. In 1987, the Ontario government established the Adoption Disclosure Registry (ADR). Adult adoptees and first relatives could register with the ADR. Adoptees and first parents also won the right to apply to the organization which handled the adoption—in many cases, a Children's Aid Society (CAS)—to receive non-identifying background information about the family member lost through adoption.

Throughout the twentieth century, the CASs actively persuaded pregnant unmarried women to relinquish their children rather than try and raise them as single mothers. This complimented a societal view that out-of-wedlock pregnancies were immoral and the women who found themselves pregnant were in need of correction and punishment. Few, if any, economic “crutches” were in place to help women support themselves and their babies. As a result, many women surrendered children whom they wanted to keep. Recent research has shown that many of these women never forgot their children and, in fact, lived for many years with a deep but secret longing for reunion.

In the latter quarter of the twentieth century, many adoptees and first relatives joined together to form adoption reunion groups. Individual members, who have become adept at searching for missing unidentified members of the adoption community, provide assistance and support for others as they begin their search. Some therapists and psychiatrists have come to realize that adoption affects individuals in a variety of primarily negative ways.