Sometimes people of mixed African-American and Native American descent report having had elder family members withholding pertinent genealogical information. Tracing the genealogy of African Americans can be a very difficult process, as censuses did not identify slaves by name before the American Civil War, meaning that most African Americans did not appear by name in those records. In addition, many white fathers who used slave women sexually, even those in long-term relationships like Thomas Jefferson's with Sally Hemings, did not acknowledge their mixed-race slave children in records, so paternity was lost.