In April 2012, the Boston Herald drew attention to Warren's law directory entries from 1986 to 1995, in which she had self-identified as having Native American ancestry. Because of these entries, Harvard Law School had added her to a list of minority professors in response to criticisms about a lack of faculty diversity. Warren said that she was unaware that Harvard had done so until she read about it in a newspaper. According to Warren and her brothers, they grew up "listening to our mother and grandmother and other relatives talk about our family’s Cherokee and Delaware heritage". The New England Historical Genealogical Society found no documentary proof of Warren having Native American lineage, but a spokesperson from the Oklahoma Historical Society said "finding a definitive answer about Native American heritage can be difficult, not only because of intermarriage, but also because some Native Americans opted not to be put on federal rolls, while others who were not Native American did put their names on rolls to get access to land." Her ethnicity claims became the focus of the media's election coverage for a certain time, during which her opponents bought ads asking her for explanations and to "come clean about her motivations" and some members of the Cherokee Nation asked how her claim influenced universities interested in hiring her. Colleagues and supervisors at the schools where she had worked publicly supported her statement that she did not receive preferential treatment. In polls, 72% of voters said the issue would not impact their vote in the election