A national sample of US paternity tests: do demographics predict test outcomes?

Nearly 300,000 paternity tests are performed in the United States annually to include or exclude a male as the biological father of a child. Little is known about how well the test outcomes could be predicted simply on the basis of the subjects' social background. Our objective is to document the demographic composition of test subjects and to determine how well ethnic background and age predict paternity inclusion.

A national database of 9999 paternity test results was formed weighted to represent the population of paternity establishment cases for the United States. Multiple regression determined the odds ratio of a paternity inclusion based on demographic variables such as race and age.

The test results indicated paternity inclusions in 72 percent of cases, overall. The percent included varied little across racial and/or ethnic categories with a low of 67 percent in African Americans and a high of 82 percent among Native Americans, but these differences were not significant in multivariate analysis. The likelihood of inclusion showed a modest but significant correlation with increased maternal age. Mothers of European origin who nominated non-Europeans as fathers were less likely to identify the correct man as father.

For any subject receiving a genetic test in a child support office, predicting a 72 percent probability that the test will show paternity inclusion offers as good an estimate of the test outcome as a subgroup estimate based on a subject's age, race, and child characteristics.