How well does paternity confidence match actual paternity? Evidence from worldwide nonpaternity rates

Little is known about how accurately men’s confidence of paternity reflects actual paternity. Are men with high paternity confidence more likely to be fathers than men with low paternity confidence? A sample of 67 worldwide nonpaternity rates is divided into three categories: high paternity confidence (N = 22, mostly from genetic studies), low paternity confidence (N = 31, containing men who contested paternity through paternity tests), and unknown paternity confidence (N = 14, mostly unpublished studies). The results show that men with high paternity confidence have very low rates of nonpaternity (median = 1.7%), while men with low paternity confidence have much higher levels of nonpaternity (median = 29.8%). When men with low and unknown paternity confidence levels are combined, the median nonpaternity rate is 3.3%. These levels are all significantly different from one another (Wilcoxon sign-rank test), confirming that men with high paternity confidence are more accurate in their assessment of paternity than men with low paternity confidence. These differences in nonpaternity between these groups remain when compared by geographical region (U.S., Europe, and elsewhere).