This paper begins by examining federal paternity standards involving voluntary paternity acknowledgments of children born to unmarried women. These standards are increasingly important as voluntary acknowledgments are now typically required for birth certificate recognitions of paternity for children born to unmarried women and as the number of births to unmarried women in the United States has doubled in the past two decades. The paper then explores the confusion in Illinois over these standards arising from the 2004 Illinois Supreme Court decision in People v. Smith. It then illustrates that there is similar confusion nationwide. For example, there is much doubt about what happens when males initiate paternity disestablishment proceedings seeking to rescind voluntary paternity acknowledgments based on lack of genetic ties. Next, the paper reviews other paternity disestablishment standards in Illinois. In doing so, it reveals that the conditions for paternity disestablishment frequently are dependent upon legal distinctions that are, at the least, unsound (and perhaps unconstitutional). The paper concludes with suggested reforms for both federal and Illinois laws on initial paternity designations and on later paternity disestablishments.