Having a Daughter May Change How Fathers Treat Their Partners, Research Suggests

Fathers with daughters tend to invest more in their romantic relationships than fathers with sons, according to new psychological research. The findings suggest that the sex of a child can subtly reshape a father’s relationship priorities in ways that may contribute to long-term family stability.

The study, published in Personality and Individual Differences, found that men with daughters reported greater commitment, satisfaction and trust toward the child’s mother. Mothers, by contrast, showed no meaningful differences in relationship quality depending on whether they had a son or daughter.

How daughters may influence fathers

The findings build on paternal investment theory, which proposes that fathers serve as an important early model of male behavior. For daughters, a father’s reliability and involvement may help shape expectations about whether future romantic partners will be supportive and committed.

Earlier research has found that girls who grow up with absent or disengaged fathers are more likely to begin sexual activity earlier and face a higher risk of teenage pregnancy. Other studies have associated early father absence with more casual sexual behavior in college and faster physical maturation, including earlier puberty.

Because daughters face greater physical and social costs associated with pregnancy and childcare, their success is particularly connected to reliable male support. The researchers theorized that having a daughter might therefore motivate fathers to strengthen their relationship with the mother, providing the child with a model of a stable, long-term partnership.

Three studies tracking couples over time

To investigate this possibility, a team led by Krystal Duarte and Kristina M. Durante conducted three complementary studies. The first surveyed 184 parents of one child under age 18, including 101 fathers and 83 mothers, about their attachment and relationship quality.

Fathers of daughters reported stronger emotional bonds with the child’s mother than fathers of sons. On a 9-point attachment scale, fathers of girls averaged 8.04 compared with 7.37 among fathers of boys. They also reported higher levels of commitment, satisfaction and trust.

Mothers’ responses did not differ according to their child’s sex, suggesting that the pattern was specific to fathers. The researchers then examined a large longitudinal dataset to determine whether similar differences could be observed in families followed over several years.

In the second study, the team analyzed 587 couples participating in the Fragile Families and Child Wellbeing Study, which follows parents from the birth of a child through age nine. The researchers focused on mothers’ reports of how supportive and fair their partners were as romantic partners and co-parents.

Mothers of baby girls reported receiving more partner-directed support from fathers shortly after childbirth than mothers of boys. This included greater affection, fairness and emotional support, while parenting and co-parenting behavior itself did not differ according to the child’s sex.

Fathers’ perceptions of mothers’ supportiveness also did not change depending on whether they had a son or daughter, further suggesting that the difference was primarily related to fathers’ behavior. However, the gap in romantic support gradually narrowed as the children became older.

Ruling out personality differences

The third study followed 168 first-time couples from late pregnancy through the first two years of parenthood. This allowed the researchers to examine whether fathers of daughters were already psychologically different before their children were born or whether differences emerged after birth.

Before the babies were born, expectant fathers of sons and daughters reported similar attachment styles and levels of relationship satisfaction. After birth, however, their trajectories began to diverge: fathers of daughters became more satisfied and supportive, while fathers of sons tended to become more emotionally distant.

Men with daughters also showed lower attachment anxiety, becoming more secure and less worried about their romantic relationships. Satisfaction with childcare arrangements did not differ according to whether couples had a boy or girl, reinforcing the finding that the shift was concentrated in the romantic relationship rather than parenting itself.

Across all three studies, effect sizes were small to moderate, at roughly half a standard deviation on measures such as commitment and satisfaction. This means the pattern was observable at the group level but cannot predict how any individual father will behave.

Limits, culture and open questions

The authors emphasize that the findings do not mean fathers love daughters more than sons or that fathers of boys are poor romantic partners. Instead, men with daughters appeared to show a distinct increase in behaviors that reinforced their relationship with the child’s mother.

The research involved heterosexual couples in the United States, and the authors caution that the results may not extend to other cultural environments. In societies characterized by lower paternal involvement or strong preferences for sons, the influence of a child’s sex could take a different form.

Questions also remain about why daughters might produce this effect. Previous studies have found that becoming a father is often accompanied by lower testosterone levels, which can promote caregiving, but it remains unclear whether these hormonal changes differ between fathers of daughters and fathers of sons.

Future research aims to investigate the biological and social mechanisms underlying these patterns, as well as how having multiple children of different sexes might influence family dynamics. The researchers also plan to explore how mothers and fathers may differently influence sons and daughters as their children move into adulthood.

Overall, the findings suggest that the birth of a daughter may subtly recalibrate some fathers’ relationship priorities, encouraging more visible investment in their romantic partnership. That shift, in turn, may provide daughters with an early model of steady and invested relationships that could influence their expectations later in life.

Article prepared by Victoria Caldwell.