Abandoned children were often picked up for slavery and composed a significant percentage of the Empires slave supply. Roman legal records indicate that foundlings were occasionally taken in by families and raised as a son or daughter. Although not normally adopted under Roman Law, the children, called alumni, were reared in an arrangement similar to guardianship, being considered the property of the father who abandoned them.Other ancient civilizations, notably India and China, used some form of adoption as well. Evidence suggests the goal of this practice was to ensure the continuity of cultural and religious practices; in contrast to the Western idea of extending family lines. In ancient India, secondary sonship, clearly denounced by the Rigveda, continued, in a limited and highly ritualistic form, so that an adopter might have the necessary funerary rites performed by a son. China had a similar idea of adoption with males adopted solely to perform the duties of ancestor worship.The practice of adopting the children of family members and close friends was common among the cultures of Polynesia including Hawaii where the custom was referred to as hānai. Middle ages to modern period
Adoption and commoners
The nobility of the Germanic, Celtic, and Slavic cultures that dominated Europe after the decline of the Roman Empire denounced the practice of adoption. In medieval society, bloodlines were paramount; a ruling dynasty lacking a "natural-born" heir apparent was replaced, a stark contrast to Roman traditions. The evolution of European law reflects this aversion to adoption.
Although there are a range of reasons, the most recent study of experiences of women who adopt suggests they are most likely to be 40–44 years of age, to be currently married, to have impaired fertility, and to be childless.Unrelated adoptions may occur through the following mechanisms:

Private domestic adoptions: under this arrangement, charities and for-profit organizations act as intermediaries, bringing together prospective adoptive parents with 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. Foster care adoption: this is a type of domestic adoption where a child is initially placed in public care. Many times the foster parents take on the adoption when the children become legally free. Its importance as an avenue for adoption varies by country. Of the 127,500 adoptions in the U.S. in 2000, about 51,000 or 40% were through the foster care system. International adoption: this involves the placing of a child for adoption outside that childs country of birth. This can occur through public or private agencies. In some countries, such as Sweden, these adoptions account for the majority of cases (see above table).