The next stage of adoption's evolution fell to the emerging nation of the United States. Rapid immigration and the American Civil War resulted in unprecedented overcrowding of orphanages and foundling homes in the mid-nineteenth century. Charles Loring Brace, a Protestant minister became appalled by the legions of homeless waifs roaming the streets of New York City. Brace considered the abandoned youth, particularly Catholics, to be the most dangerous element challenging the city's order.
Several factors affect the decision to release or raise the child. White adolescents tend to give up their babies to non-relatives, whereas black adolescents are more likely to receive support from their own community in raising the child and also in the form of informal adoption by relatives. Studies by Leynes and by Festinger and Young, Berkman, and Rehr found that for pregnant adolescents, the decision to release the child for adoption depended on the attitude toward adoption held by the adolescent's mother. Another study found that pregnant adolescents whose mothers had a higher level of education were more likely to release their babies for adoption. Research suggests that women who choose to release their babies for adoption are more likely to be younger, enrolled in school, and have lived in a two-parent household at age 10, than those who kept and raised their babies.
In the 1970s, as adoption search and support organizations developed, there were challenges to the language in common use at the time. As books like Adoption Triangle by Sorosky, Pannor and Baran were published, and support groups formed like CUB (Concerned United Birthparents), a major shift from "natural parent" to "birthparent" occurred. Along with the change in times and social attitudes came additional examination of the language used in 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.
Similar mechanisms appear to be at work in the physical development of adoptees. Danish and American researchers conducting studies on the genetic contribution to body mass index found correlations between an adoptee's weight class and his biological parents' BMI while finding no relationship with the adoptive family environment. Moreover, about one-half of inter-individual differences were due to individual non-shared influences.
These practices have become significant social and political issues in recent years, and in many cases the policies have changed. The United States, for example, now has the 1978 Indian Child Welfare Act, which allows the tribe and family of a Native American child to be involved in adoption decisions, with preference being given to adoption within the child's tribe.
His solution was outlined in The Best Method of Disposing of Our Pauper and Vagrant Children (1859) which started the Orphan Train movement. The orphan trains eventually shipped an estimated 200,000 children from the urban centers of the East to the nation's rural regions. The children were generally indentured, rather than adopted, to families who took them in. As in times past, some children were raised as members of the family while others were used as farm laborers and household servants. The sheer size of the displacement—the largest migration of children in history—and the degree of exploitation that occurred, gave rise to new agencies and a series of laws that promoted adoption arrangements rather than indenture. The hallmark of the period is Minnesota's adoption law of 1917 which mandated investigation of all placements and limited record access to those involved in the adoption.