Embryo adoption: based on the donation of embryos remaining after one couple's in vitro fertilization treatments have been completed; embryos are given to another individual or couple, followed by the placement of those embryos into the recipient woman's uterus, to facilitate pregnancy and childbirth. In the United States, embryo adoption is governed by property law rather than by the court systems, in contrast to traditional adoption.
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. 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.
As the idea of institutional care gained acceptance, formal rules appeared about how to place children into families: boys could become apprenticed to an artisan and girls might be married off under the institution's authority. Institutions informally adopted out children as well, a mechanism treated as a way to obtain cheap labor, demonstrated by the fact that when the adopted died, their bodies were returned by the family to the institution for burial.
In many jurisdictions the adopted person's full original birth certificate is cancelled and replaced with a fabricated post-adoption birth certificate which states that the child was born to the adoptive parents. This deception, when carried out, may continue with the adopted person for life and can be the cause for many well documented traumas experienced by the adopted person, including loss of identity, family history, culture, biological family (including not only biological parents but also siblings and extended family), family medical history and records, and increased risk of suicide, homelessness, incarceration, PTSD, depression, and anxiety.
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. 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.
Adoption practices have changed significantly over the course of the 20th century, with each new movement labeled, in some way, as reform. Beginning in the 1970s, efforts to improve adoption became associated with opening records and encouraging family preservation. These ideas arose from suggestions that the secrecy inherent in modern adoption may influence the process of forming an identity, create confusion regarding genealogy, and provide little in the way of medical history.
Some adoptees reject the idea of reunion. It is unclear, though, what differentiates adoptees who search from those who do not. One paper summarizes the research, stating, "...attempts to draw distinctions between the searcher and non-searcher are no more conclusive or generalizable than attempts to substantiate...differences between adoptees and nonadoptees."
Nevertheless, work on adult adoptees has found that the additional risks faced by adoptees are largely confined to adolescence. Young adult adoptees were shown to be alike with adults from biological families and scored better than adults raised in alternative family types including single parent and step-families. Moreover, while adult adoptees showed more variability than their non-adopted peers on a range of psychosocial measures, adult adoptees exhibited more similarities than differences with adults who had not been adopted. There have been many cases of remediation or the reversibility of early trauma. For example, in one of the earliest studies conducted, Professor Goldfarb in England concluded that some children adjust well socially and emotionally despite their negative experiences of institutional deprivation in early childhood. Other researchers also found that prolonged institutionalization does not necessarily lead to emotional problems or character defects in all children. This suggests that there will always be some children who fare well, who are resilient, regardless of their experiences in early childhood. Furthermore, much of the research on psychological outcomes for adoptees draws from clinical populations. This suggests that conclusions such that adoptees are more likely to have behavioral problems such as ODD and ADHD may be biased. Since the proportion of adoptees that seek mental health treatment is small, psychological outcomes for adoptees compared to those for the general population are more similar than some researchers propose.
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.
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.