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]
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]
^ Carlson, V., Cicchetti, D., Barnett, D., & Braunwald, K. (1995). Finding order in disorganization: Lessons from research on maltreated infants' attachments to their caregivers. In D. Cicchetti & V. Carlson (Eds), Child Maltreatment: Theory and research on the causes and consequences of child abuse and neglect (pp. 135–157). NY: Cambridge University Press.

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.[28] The children were generally indentured, rather than adopted, to families who took them in.[29] As in times past, some children were raised as members of the family while others were used as farm laborers and household servants.[30] 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.[31][32]