By the time they blow out the candles on their first birthday cake, children who look like their fathers may be healthier than those who don't share the resemblance. 

The new study, led by Solomon Polachek from Binghamton University and Marlon Tracey from Southern Illinois University, stated the resemblance makes a father spend more time engaged in positive parenting. The method of research introduces "a unique approach, with roots in evolutionary sociobiology," to study the impact of involvement from a nonresident father in a child's life.

"Fathers are important in raising a child, and it manifests itself in the health of the child," said Polachek, distinguished research professor of Economics at Binghamton.

The team used data from the Fragile Families and Child Wellbeing (FFCW) study that examined 715 families in which children (born between 1998 and 2000) lived only with their mothers. It was considered appropriate as "paternity uncertainty is more likely to prevail among fragile families," according to the study. The FFCW data recorded the appearance of babies at birth from the responses of both the parents to the question: "Who does the baby look like?"

"Because women do not need facial resemblance cues to decide whether to provide care, we expect baby looks affect child developmental outcomes only through a father's investments," the study stated, highlighting the distinct nature of the paternal investment. 

Data from the first two waves of the study indicated infants who looked like their fathers at birth were healthier one year later. 

"Those fathers that perceive the baby's resemblance to them are more certain the baby is theirs, and thus spend more time with the baby," explained Polachek.

This prediction, as per the researchers, is supported by prior experimental studies based on animal/human families in evolution-related disciplines, but has not been used in economic research to date. 

Researchers referred to time investment as "a key channel" as findings showed the father-child resemblance acted as "a paternity cue used by men especially for making time-investment decisions." 

These fathers, on an average, spent 2.5 more days per month with their babies than those who didn't resemble their offspring. Inevitably, it had implications regarding the role of a father's time in enhancing child health, especially in fragile families.

"We find a child's health indicators improve when the child looks like the father...The main explanation is that frequent father visits allow for greater parental time for caregiving and supervision, and for information gathering about child health and economic needs. It's been said that 'it takes a village' but my coauthor, Marlon Tracey, and I find that having an involved father certainly helps," said Polachek.

For the improvement of early childhood health, researchers have expressed support for policies encouraging nonresident fathers to engage in regular positive parenting. Polachek stated these fathers could be provided adequate support through parenting classes, health education, and job training to enhance earnings.