The period 1945 to 1974, the baby scoop era, saw rapid growth and acceptance of adoption as a means to build a family.[40] Illegitimate births rose three-fold after World War II, as sexual mores changed. Simultaneously, the scientific community began to stress the dominance of nurture over genetics, chipping away at eugenic stigmas.[41][42] In this environment, adoption became the obvious solution for both unwed people and infertile couples.[43]
The research literature states adoptees give four reasons for desiring reunion: 1) they wish for a more complete genealogy, 2) they are curious about events leading to their conception, birth, and relinquishment, 3) they hope to pass on information to their children, and 4) they have a need for a detailed biological background, including medical information. It is speculated by adoption researchers, however, that the reasons given are incomplete: although such information could be communicated by a third-party, interviews with adoptees, who sought reunion, found they expressed a need to actually meet biological relations.[167]

Unlike guardianship or other systems designed for the care of the young, adoption is intended to effect a permanent change in status and as such requires societal recognition, either through legal or religious sanction. Historically, some societies have enacted specific laws governing adoption; where others have tried to achieve adoption through less formal means, notably via contracts that specified inheritance rights and parental responsibilities without an accompanying transfer of filiation. Modern systems of adoption, arising in the 20th century, tend to be governed by comprehensive statutes and regulations.

Concerning developmental milestones, studies from the Colorado Adoption Project examined genetic influences on adoptee maturation, concluding that cognitive abilities of adoptees reflect those of their adoptive parents in early childhood but show little similarity by adolescence, resembling instead those of their biological parents and to the same extent as peers in non-adoptive families.[114]

Adoptions can occur either between related family members, or unrelated individuals. Historically, most adoptions occurred within a family. The most recent data from the U.S. indicates about half of adoptions are currently between related individuals.[78] A common example of this is a "stepparent adoption", where the new partner of a parent may legally adopt a child from the parent's previous relationship. Intra-family adoption can also occur through surrender, as a result of parental death, or when the child cannot otherwise be cared for and a family member agrees to take over.
The majority of people state that their primary source of information about adoption comes from friends and family and the news media. Nevertheless, most people report the media provides them a favorable view of adoption; 72% indicated receiving positive impressions.[145] There is, however, still substantial criticism of the media's adoption coverage. Some adoption blogs, for example, criticized Meet the Robinsons for using outdated orphanage imagery[146][147] as did advocacy non-profit The Evan B. Donaldson Adoption Institute.[148]
The biological relationship between a parent and child is important, and the separation of the two has led to concerns about adoption. The traditional view of adoptive parenting received empirical support from a Princeton University study of 6,000 adoptive, step, and foster families in the United States and South Africa from 1968 to 1985; the study indicated that food expenditures in households with mothers of non-biological children (when controlled for income, household size, hours worked, age, etc.) were significantly less for adoptees; step-children, and foster children, causing the researchers to speculate that, instinctively, people are less interested in sustaining the genetic lines of others.[92] This theory is supported in another more qualitative study where in adoptive relationships marked by sameness in likes, personality, and appearance, both adult adoptees and adoptive parents report being happier with the adoption.[93]

Reform and family preservation efforts have also been strongly associated with the perceived misuse of adoption. In some cases, parents' rights have been terminated when their ethnic or socio-economic group has been deemed unfit by society. Some of these practices were generally accepted but have later been considered abusive; others were uncontroversially reprehensible.

When another family is ready to adopt the child, DFPS and the family complete the adoptive placement paperwork. After children have lived in their new home for six months, the adoptive family and CPS can make the adoption permanent. In many cases, the children may have already been living with the family as a kinship care or foster home so they are familiar with their new family. The adoptive family can submit a document to court called a "petition to adopt" and, if approved by a judge, the adoption becomes permanent (also known as "consummated"). At this point, CPS is dismissed from the child's case, and DFPS will no longer be involved with the child or your family.

Taken together, these trends resulted in a new American model for adoption. Following its Roman predecessor, Americans severed the rights of the original parents while making adopters the new parents in the eyes of the law. Two innovations were added: 1) adoption was meant to ensure the "best interests of the child;" the seeds of this idea can be traced to the first American adoption law in Massachusetts,[16][23] and 2) adoption became infused with secrecy, eventually resulting in the sealing of adoption and original birth records by 1945. The origin of the move toward secrecy began with Charles Loring Brace who introduced it to prevent children from the Orphan Trains from returning to or being reclaimed by their parents. Brace feared the impact of the parents' poverty, in general, and their Catholic religion, in particular, on the youth. This tradition of secrecy was carried on by the later Progressive reformers when drafting of American laws.[44]

Externally focused theories, in contrast, suggest that reunion is a way for adoptees to overcome social stigma. First proposed by Goffman, the theory has four parts: 1) adoptees perceive the absence of biological ties as distinguishing their adoptive family from others, 2) this understanding is strengthened by experiences where non-adoptees suggest adoptive ties are weaker than blood ties, 3) together, these factors engender, in some adoptees, a sense of social exclusion, and 4) these adoptees react by searching for a blood tie that reinforces their membership in the community. The externally focused rationale for reunion suggests adoptees may be well adjusted and happy within their adoptive families, but will search as an attempt to resolve experiences of social stigma.[167]