I had written about a study quantifying the number of fathers who aren't really fathers of their children, even though they think they are. The study has now appeared in the latest issue of Current Anthropology
CURRENT ANTHROPOLOGY Volume 47, Number 3, June 2006
How Well Does Paternity Confidence Match Actual Paternity?
Evidence from Worldwide Nonpaternity Rates
Kermyt G. Anderson
Evolutionary theory predicts that males will provide less parental investment for putative offspring who are unlikely to be their actual offspring. Cross-culturally, paternity confidence (a man's assessment of the likelihood that he is the father of a putative child) is positively associated with men's involvement with children and with investment or inheritance from paternal kin. A survey of 67 studies reporting nonpaternity suggests that for men with high paternity confidence rates of nonpaternity are(excluding studies of unknown methodology) typically 1.9%, substantially less than the typical rates of 10% or higher cited by many researchers. Further cross-cultural investigation of the relationship between paternity and paternity confidence is warranted.