Why mothers say that babies look more like their fathers

There is a common belief that babies tend to look more like their fathers than their mothers, a claim with a reasonable evolutionary explanation.

The theory
Because a father doesn’t share the mother’s certainty that a baby is his, and is more likely to invest whatever resources he has in his own offspring. Thus, human evolution could have favored children that resemble their fathers, at least early on, as a way of confirming paternity.

A study published in 1995 in Nature Magazine backed the idea. It showed that people were much better at matching photos of one-year-old children with pictures of their fathers than with photos of their mothers.

A new round of studies
However, further research published over the years in the journal, Evolution & Human Behavior, conflicted with the 1995 findings, indicating that children resemble both parents equally. Some studies even found that newborns tend to resemble their mothers more than their fathers.

Recently, researchers tried to replicate the results from 1995 and used more sets of photos than the amount used in the original experiment. In the photo-matching trial with pictures of one-year-old, three-year-old, and five-year-old children and their parents, subjects identified mothers and fathers equally well.

According to one of the researchers, the research on a much larger sample of babies shows that some babies resemble their father more, some babies resemble their mother more, and most babies resemble both parents to about the same extent.

A new theory
Two other studies, one in 2000 and one in 2007, found that newborns actually look more like their mothers than their fathers in the first three days of their lives, as judged by unrelated assessors. However, they also found out that the mothers tend to say the opposite, emphasizing the child’s resemblance to the father. This may be so that the father accepts the child as his, even if it is not.