This system of apprenticeship and informal adoption extended into the 19th century, today seen as a transitional phase for adoption history. Under the direction of social welfare activists, orphan asylums began to promote adoptions based on sentiment rather than work; children were placed out under agreements to provide care for them as family members instead of under contracts for apprenticeship.[21] The growth of this model is believed to have contributed to the enactment of the first modern adoption law in 1851 by the Commonwealth of Massachusetts, unique in that it codified the ideal of the "best interests of the child."[22][23] Despite its intent, though, in practice, the system operated much the same as earlier incarnations. The experience of the Boston Female Asylum (BFA) is a good example, which had up to 30% of its charges adopted out by 1888.[24] Officials of the BFA noted that, although the asylum promoted otherwise, adoptive parents did not distinguish between indenture and adoption; "We believe," the asylum officials said, "that often, when children of a younger age are taken to be adopted, the adoption is only another name for service."[25]
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]
In sum, reunions can bring a variety of issues for adoptees and parents. Nevertheless, most reunion results appear to be positive. In the largest study to date (based on the responses of 1,007 adoptees and relinquishing parents), 90% responded that reunion was a beneficial experience. This does not, however, imply ongoing relationships were formed between adoptee and parent nor that this was the goal.[170]
The language of adoption is changing and evolving, and since the 1970s has been a controversial issue tied closely to adoption reform efforts. The controversy arises over the use of terms which, while designed to be more appealing or less offensive to some persons affected by adoption, may simultaneously cause offense or insult to others. This controversy illustrates the problems in adoption, as well as the fact that coining new words and phrases to describe ancient social practices will not necessarily alter the feelings and experiences of those affected by them. Two of the contrasting sets of terms are commonly referred to as positive adoption language (PAL) (sometimes called respectful adoption language (RAL)), and honest adoption language (HAL).
There are supporters of various lists, developed over many decades, and there are persons who find them lacking, created to support an agenda, or furthering division. All terminology can be used to demean or diminish, uplift or embrace. In addressing the linguistic problem of naming, Edna Andrews says that using "inclusive" and "neutral" language is based upon the concept that "language represents thought, and may even control thought."[190]
There is limited research on the consequences of adoption for the original parents, and the findings have been mixed. One study found that those who released their babies for adoption were less comfortable with their decision than those who kept their babies. However, levels of comfort over both groups were high, and those who released their child were similar to those who kept their child in ratings of life satisfaction, relationship satisfaction, and positive future outlook for schooling, employment, finances, and marriage.[121] Subsequent research found that adolescent mothers who chose to release their babies for adoption were more likely to experience feelings of sorrow and regret over their decision than those who kept their babies. However, these feelings decreased significantly from one year after birth to the end of the second year.[122]
Adoption practices have changed significantly over the course of the 20th century, with each new movement labeled, in some way, as reform.[152] 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,[153][154] create confusion regarding genealogy,[155] and provide little in the way of medical history.
Private domestic adoptions: under this arrangement, charities and for-profit organizations act as intermediaries, bringing together prospective adoptive parents and families who want to place a child, all parties being residents of the same country. Alternatively, prospective adoptive parents sometimes avoid intermediaries and connect with women directly, often with a written contract; this is not permitted in some jurisdictions. Private domestic adoption accounts for a significant portion of all adoptions; in the United States, for example, nearly 45% of adoptions are estimated to have been arranged privately.[83]

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.[19] 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.[20]
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.[19] 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.[20]
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.[137] 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.[138] 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.[139] 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.[140] 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.[141]

The research says that the dysfunction, untruths and evasiveness that can be present in adoptive families not only makes identity formation impossible, but also directly works against it. What effect on identity formation is present if the adoptee knows they are adopted but has no information about their biological parents? Silverstein and Kaplan's research states that adoptees lacking medical, genetic, religious, and historical information are plagued by questions such as "Who am I?" "Why was I born?" "What is my purpose?" This lack of identity may lead adoptees, particularly in adolescent years, to seek out ways to belong in a more extreme fashion than many of their non-adopted peers. Adolescent adoptees are overrepresented among those who join sub-cultures, run away, become pregnant, or totally reject their families.[133][134]

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]