Evidence about the development of adoptees can be supported in newer studies. It can be said that adoptees, in some respect, tend to develop differently from the general population. This can be seen in many aspects of life, but usually can be found as a greater risk around the time of adolescence. For example, it has been found that many adoptees experience difficulty in establishing a sense of identity.[126]
Previous research on adoption has led to assumptions that indicate that there is a heightened risk in terms of psychological development and social relationships for adoptees. Yet, such assumptions have been clarified as flawed due to methodological failures. But more recent studies have been supportive in indicating more accurate information and results about the similarities, differences and overall lifestyles of adoptees.[125]

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).

The stigmas associated with adoption are amplified for children in foster care.[149] Negative perceptions result in the belief that such children are so troubled it would be impossible to adopt them and create "normal" families.[150] A 2004 report from the Pew Commission on Children in Foster Care has shown that the number of children waiting in foster care doubled since the 1980s and now remains steady at about a half-million a year."[151]
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.
In another study that compared mothers who released their children to those who raised them, mothers who released their children were more likely to delay their next pregnancy, to delay marriage, and to complete job training. However, both groups reached lower levels of education than their peers who were never pregnant.[124] Another study found similar consequences for choosing to release a child for adoption. Adolescent mothers who released their children were more likely to reach a higher level of education and to be employed than those who kept their children. They also waited longer before having their next child.[122] Most of the research that exists on adoption effects on the birth parents was conducted with samples of adolescents, or with women who were adolescents when carrying their babies—little data exists for birth parents from other populations. Furthermore, there is a lack of longitudinal data that may elucidate long-term social and psychological consequences for birth parents who choose to place their children for adoption.
International adoption: involves the placing of a child for adoption outside that child's country of birth. This can occur through both public and private agencies. In some countries, such as Sweden, these adoptions account for the majority of cases (see above Table). The U.S. example, however, indicates there is wide variation by country since adoptions from abroad account for less than 15% of its cases.[83] More than 60,000 Russian children have been adopted in the United States since 1992,[85] and a similar number of Chinese children were adopted from 1995 to 2005.[86] The laws of different countries vary in their willingness to allow international adoptions. Recognizing the difficulties and challenges associated with international adoption, and in an effort to protect those involved from the corruption and exploitation which sometimes accompanies it, the Hague Conference on Private International Law developed the Hague Adoption Convention, which came into force on 1 May 1995 and has been ratified by 85 countries as of November 2011.[87]
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.