A baby girl appears to alter a father’s relationship priorities in one highly specific way

Having a daughter appears to shift a father’s focus toward maintaining a strong romantic relationship with the child’s mother. The research suggests that fathers of daughters show higher levels of commitment and relationship satisfaction compared to fathers of sons. These findings, published in Personality and Individual Differences, provide evidence that a child’s sex can influence a father’s psychology in ways that promote long-term family stability.

The foundation of this research rests on paternal investment theory, a framework suggesting that fathers serve as an early model of male behavior for their children. For daughters in particular, a father’s presence and level of involvement provide information about whether men in the broader social environment are reliable and likely to invest in long-term relationships. When a father is absent or uninvolved, daughters tend to adjust their expectations and sexual strategies to fit a world where male support is unpredictable.

For instance, a 2003 longitudinal study found that girls who grew up with an absent father were more likely to engage in early sexual activity and experience teenage pregnancy. Along similar lines, a study covered by PsyPost in 2016 indicated that an earlier age of father absence is linked to a higher number of casual sexual encounters during college. Another line of research, such as a study covered by PsyPost in 2026, has found that father absence during specific developmental windows is associated with accelerated physical maturation, including an earlier onset of puberty.

Because daughters bear the higher physical costs of pregnancy and childcare, their reproductive success is especially sensitive to signs of reliable male support. The researchers hypothesized that having a daughter might prompt fathers to maintain a stronger pair-bond with the mother. By demonstrating a stable relationship, fathers model reliable male investment, which might encourage daughters to delay reproduction and seek out committed partners.

“But no prior study had looked at the reverse, the impact having a daughter has on a man,” Kristina M. Durante, a professor of marketing and research fellow at the Center for Women in Business at Rutgers Business School, told PsyPost. “This was a significant gap, especially given that one of the leading theories for why father absence negatively impacts daughters is because fathers send a message to a daughter about what to expect from a future partner.” The research, led by Krystal Duarte alongside Durante, aimed to test whether fathers of daughters display stronger pair-bond motivation than fathers of sons.

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To investigate this dynamic, the researchers conducted three separate studies. In the first study, the team surveyed 184 parents with a single child under the age of 18. The sample included 101 fathers and 83 mothers. Participants completed questionnaires assessing their emotional attachment to their partner and various components of their relationship quality, such as satisfaction, commitment, and trust.

The results indicated that fathers of daughters reported stronger attachment bonds to the child’s mother than fathers of sons. On a 9-point scale measuring attachment strength, fathers with daughters averaged a score of 8.04, compared to 7.37 for fathers of sons. Fathers of daughters also reported higher levels of relationship commitment, satisfaction, and trust. In contrast, mothers’ reports of relationship quality and attachment did not differ based on whether they had a son or a daughter.

For the second study, the researchers analyzed data from a large, long-term project called the Fragile Families and Child Wellbeing Study. This dataset allowed them to examine how mothers perceived their partners’ behavior over several years, from the child’s birth up to age nine. The final sample included 587 couples. The team measured both partner-directed support, such as showing affection and fairness toward the mother, and parenting-focused support, such as cooperating on childcare rules.

Mothers who had a daughter reported receiving more partner-directed support from fathers shortly after childbirth compared to mothers who had a son. This difference in romantic relationship support was specific to the parents’ dynamic as a couple, as the researchers found no differences in general parenting or co-parenting behaviors based on the child’s sex. Additionally, fathers’ perceptions of the mothers’ supportiveness did not vary depending on whether they had a boy or a girl.

“Outside of finding that daughters have an impact on dads, we were surprised and delighted to see that dads of daughters were reported to be better partners by the mother,” Durante noted. “So, this isn’t just dad ‘reporting’ that he is a more committed partner, moms are feeling that commitment through his behavior.” Over time, the gap in partner support between fathers of daughters and fathers of sons appeared to narrow as the children grew older.

The third study aimed to rule out the possibility that preexisting personality differences between men who have daughters and men who have sons were driving the results. The researchers tracked 168 first-time parent couples from their third trimester of pregnancy through the first two years of their child’s life. Participants reported on their relationship satisfaction, romantic attachment styles, and feelings about childcare at multiple points before and after the birth.

Before the babies were born, there were no differences in relationship quality or attachment between the expectant fathers of sons and those expecting daughters. After childbirth, however, fathers of daughters reported greater relationship satisfaction and provided more support to their partners. They also showed decreases in attachment anxiety, meaning they became more secure and less worried about their relationship.

Meanwhile, fathers of sons tended to become more avoidant, pulling away emotionally, and less satisfied with their relationship over time. Once again, these shifts were specific to the romantic pair-bond, as satisfaction with childcare duties did not change based on the child’s sex. By tracking these changes across the transition to parenthood, the study provides evidence that the birth of a daughter directly relates to a reconfiguration of a father’s romantic motivations.

“Having a daughter seems to shift dads toward greater investment in their relationship with the child’s mother, not just toward the kid, but toward the marriage/partnership itself,” Durante explained. “This showed up across three different methods (self-report, partner-report over time, and before-vs-after having the baby), which is what makes it compelling: it’s not just ‘dads of daughters say nice things,’ it’s that fathers’ actual relationship behavior appears to change after a daughter is born.”

“These are small-to-medium effects, which means differences of about half a standard deviation on measures like commitment and relationship satisfaction, not full standard deviations,” she added. “The effect isn’t large enough to predict any single father’s behavior, but it’s consistent enough, showing up across three independent studies using different methods, to suggest something real and biologically patterned is going on beneath the surface.”

As with all research, there are a few things to keep in mind. “It’s not that dads love daughters more than sons,” Durante clarified. “It’s not that fathers of sons are bad partners. Sons’ fathers didn’t get worse, so much as daughters’ fathers showed a distinctive uptick in pair-bond-focused behavior.”

“This is an effect we found in the US and may not translate to other non-Western populations,” Durante pointed out. In societies where fathers are less involved in daily family life, or in places with a strong cultural preference for sons, the effects of a child’s sex on a father’s relationship behavior might look quite different. The research also focused on heterosexual couples, leaving it an open question whether similar dynamics exist in non-heterosexual partnerships.

Future studies could explore the exact biological or social mechanisms that relate to this shift in fathers. For instance, the transition to fatherhood is known to correspond with drops in testosterone, which encourages caregiving. However, it is not yet known if having a daughter influences these hormonal changes more than having a son. Exploring how the sex of multiple siblings interacts to influence a father’s relationship behavior could also provide a more detailed picture of family dynamics.

“We are continuing to look at how a person’s early experience with mom and dad impacts their behavior in adulthood,” Durante said. “We are looking closely at how moms may differentially influence the development of sons versus daughters.”

“Becoming a father to a daughter may recalibrate a man’s relationship priorities, nudging him to be a more visibly committed partner, possibly because daughters are especially attuned to what their father’s relationship teaches them about what to expect for a future partner,” she concluded.

The study, “Daughters promote pair-bonding in fathers in modern Western cultures,” was authored by Krystal Duarte, Kristina M. Durante, Jeffrey Gassen, Americus Reed, Steven Rholes, and Jeffry A. Simpson.