Assuming no freak hospital mix-ups, mothers can be 100% sure that a child that she bears and raises is, in fact, genetically her own. Fathers, however, can’t be quite so sure. Even if “dad” engages in vigilant mate guarding, there’s always the possibility that his partner snuck off for some horizontal mambo action with another guy. Evolutionary psychologists call this the “paternal certainty problem”— men who have been cuckolded and are unknowingly raising a child that’s not their own have failed, from an evolutionary perspective, at passing on their genes. And it turns out that a significant number of men have failed to solve this problem. Think this doesn’t happen? Well, rates of non-paternity have been reported to be as high as 10%,1 although a more realistic estimate is somewhere in the 2-3% range.2 So, if you line up 100 dads and “their” kids in a room, chances are that 2 or 3 of the dads are standing with some other guy’s kid.

If a man can’t always be sure that “his” child is in fact his, what clues might he use to feel a bit more confident in his baby-daddy status? First, men monitor their mates’ behavior and tend to become especially upset at thought of their girlfriends/wives cheating. Clearly, no one likes the idea of their partners getting it on with someone else (cuckold fetishes aside, but we’ll save that for another post), but men are especially bothered by sexual infidelity compared to women and relative to emotional infidelity (i.e., falling in love with someone else).3

Second, “dad” can size-up the baby and see if it looks like him. In one seminal (no pun intended) study, raters were more likely to correctly match pictures of infants with biological fathers than biological mothers (i.e., babies looked more like dad than mom);4 however, this finding has not been replicated by subsequent research.5,6 Interestingly, dads who think their kids look like them tend to have more positive relationships with those children.7 It makes sense that mothers (and mothers’ relatives) are more likely to say that a baby looks like the father, possibly as a form of reassuring the father of his paternity.8 Although, to be fair, there is just something about a bald chubby baby that looks more “dad-like” than “mom-like.”

Clearly, men are concerned with their biological relatedness to their (supposed) children, and adaptive mechanisms to reassure them of their fatherhood may have evolved. But there is still plenty of paternity confusion going on in relationships, as evidenced by the never-ending supply of drama on the Jerry Springer show.

Sponsored: What about paternity testing?

The only way of being sure of whether you are the real daddy is by doing a home paternity test. This DNA test is simple to carry out: The father in doubt needs to find an online company offering such tests and request a DNA sampling kit. Once he receives the kit he will need to use the swabs within to collect DNA samples from himself and the child. The ease of collecting samples with oral swabs makes them ideal for such a test. All that needs to be done is rub the swabs under the tongue and against the cheek for a couples of seconds and then left to dry. Once dry, they need to be sent back for laboratory analysis.

Perhaps some fathers wish to do the test a bit more discretely than with oral swabs! Well this too would not be a problem as many companies offer alternative types of DNA samples that can be used for paternity testing: used Kleenexes, blood stains, nail clippings, teeth and the list goes on and on. As to the results, the most important part of the test: if the dad tested is the real father, the result will show a percentage probability of 99.9% or higher. If he is not the daddy of the child, then this probability will be 0%.

Until next time, take care of yourself…and each other.

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1MacIntyre, S., & Sooman, A. (1991). Nonpaternity and prenatal genetic screening. Lancet, 338, 869-871.

2Anderson, K. G. (2006). How well does paternity confidence match actual paternity? Evidence from worldwide nonpaternity rates. Current Anthropology, 47, 513-520.

3Buunk, B. P., Angleitner, A., Oubaid, V., & Buss, D. M. (1996). Sex differences in jealousy in evolutionary and cultural perspective: Tests from the Netherlands, Germany, and the United States. Psychological Science, 7, 359-363.

4Christenfeld, N. J. S., & Hill, E. A. (1995). Whose baby are you? Nature, 378, 669.

5Brédart, S., & French, R. (1999). Do babies resemble their fathers more than their mothers? A failure to replicate Christenfeld and Hill. Evolution and Human Behavior, 20, 129-135.

6Alvergne A., Faurie, C., & Raymond, M. (2007). Differential facial resemblance of young children to their parents: Who do children look like more? Evolution and Human Behavior, 28, 135-144.

7Burch, R. L., & Gallup, G. G. Jr. (2000). Perceptions of paternal resemblance predict family violence. Evolution and Human Behavior 21, 429-435.

8Daly, M., & Wilson, M. I. (1982). Whom are newborn babies said to resemble? Ethology and Sociobiology, 3, 69-78.

Dr. Benjamin Le – Science of Relationships articles | Website/CV

Dr. Le’s research focuses on commitment, including the factors associated with commitment and its role in promoting maintenance. He has published on the topics of breakup, geographic separation, infidelity, social networks, cognition, and need fulfillment and emotions in relationships.