4) they have a need for a detailed biological background, including medical information. It is speculated by adoption researchers, however, that the reasons given are incomplete: although such information could be communicated by a third-party, interviews with adoptees, who sought reunion, found they expressed a need to actually meet biological relations. It appears the desire for reunion is linked to the adoptee's interaction with and acceptance within the community. Internally focused theories suggest some adoptees possess ambiguities in their sense of self, impairing their ability to present a consistent identity. Reunion helps resolve the lack of self-knowledge. Externally focused theories, in contrast, suggest that reunion is a way for adoptees to overcome social stigma. First proposed by Goffman, the theory has four parts: 1) adoptees perceive the absence of biological ties as distinguishing their adoptive family from others, 2) this understanding is strengthened by experiences where non-adoptees suggest adoptive ties are weaker than blood ties, 3) together, these factors engender, in some adoptees, a sense of social exclusion, and 4) these adoptees react by searching for a blood tie that reinforces their membership in the community. The externally focused rationale for reunion suggests adoptees may be well adjusted and happy within their adoptive families, but will search as an attempt to resolve experiences of social stigma. Some adoptees reject the idea of reunion. It is unclear, though, what differentiates adoptees who search from those who do not. One paper summarizes the research, stating, "...attempts to draw distinctions between the searcher and non-searcher are no more conclusive or generalizable than attempts to substantiate ... differences between adoptees and nonadoptees." In sum, reunions can bring a variety of issues for adoptees and parents. Nevertheless, most reunion results appear to be positive. In the largest study to date (based on the responses of 1,007 adoptees and relinquishing parents), 90% responded that reunion was a beneficial experience. This does not, however, imply ongoing relationships were formed between adoptee and parent nor that this was the goal. Controversial adoption practices Reform and family preservation efforts have also been strongly associated with the perceived misuse of adoption. In some cases, parents' rights have been terminated when their ethnic or socio-economic group has been deemed unfit by society. Some of these practices were generally accepted but have later been considered abusive; others were uncontroversially reprehensible. Forced adoption based on ethnicity occurred during World War II. In German-occupied