Open adoption is a form of adoption in which the biological and adoptive families have access to varying degrees of each other's personal information and have an option of contact. While open adoption is a relatively new phenomenon in the west, it has been a traditional practice in many Asian societies, especially in South Asia, for many centuries. In Hindu society, for example, it is relatively common for a childless couple to adopt the second or later son of the husband's brother when the childless couple has limited hope of producing their own child. In an open adoption, the adoptive parents hold all the rights as the legal parents, yet the individuals of the biological and adoptive families may exercise the option to open the contact in varying forms: from just sending mail and/or photos, to face-to-face visits between birth and adoptive families. History of openness in adoption Although open adoptions are thought to be a relatively new phenomenon, most adoptions in the United States until the twentieth century were open. Until the 1930s, most adoptive parents and biological parents had contact at least during the adoption process. In many cases, adoption was seen as a social support: young children were adopted out not only to help their parents (by reducing the number of children they had to support) but also to help another family by providing an apprentice. Adoptions became closed when social pressures mandated that families preserve the myth that they were formed biologically. One researcher has referred to these families, that made every attempt to match the child physically to their adoptive families, as 'as if' families. Open adoption has slowly become more common since research in the 1970s suggested that open adoption was better for children. In 1975 the tide began to change, and by the early 1990s open adoptions were offered by a majority of American adoption agencies. Especially rapid progress was seen in the late 1980s and early 1990s - between 1987 and 1989 a study found only a third of agencies offered fully open adoption as an option; by 1993 76 percent of the surveyed agencies offered fully open adoptions. As of 2013, roughly half of US states consider them legally binding, however contact in open adoption is not always maintained. The social stigma of unmarried motherhood, particularly during the Baby Scoop Era (1945-1975) rendered single mothers as social outcasts. By the 1980s,