In the past decade or so, scientists have assembled an impressive amount of evidence that becoming a father transforms men's bodies. Moreover, children can be positively affected by the distinct way that fathers typically engage their children. Writing at IAV/Magazine my colleagues Kathleen Kovner Kline and W. Bradford Wilcox, co-authors of the new research summary Mother Bodies, Father Bodies: How Parenthood Changes Us from the Inside Out, describe how "men's biology is hardwired to assume the responsibilities and develop the capacities to nurture, respond, guide and protect their children."
Here are seven findings from the new science of fatherhood, gleaned from the new report, as well as from the edited volume of essays upon which the report is based, Gender and Parenthood: Biological and Social Scientific Perspectives.
1. Involved fathers typically experience a series of hormonal changes before and after birth that focus them on their children.
As the hard sciences are showing us, men who have frequent contact with the mother during pregnancy experience changes in several important hormones.
As Kline and Wilcox point out, before birth men may experience changes in the hormones cortisol, estrogen, testosterone, and prolactin (the same hormone that helps mothers make milk). After birth, fathers who care for their children typically experience a drop in testosterone--which is significant because less testosterone in men is associated with more responsive parenting. For instance, in one study, men with lower levels of testosterone held test baby dolls longer and were more responsive to infants' cries than were men with higher testosterone. The testosterone drop after birth is despite the fact that, according to one study, men with higher testosterone levels were more likely to become fathers than men with lower testosterone.
2. Fathers are just as capable as mothers of providing affectionate, nurturing care.
One study by psychologist Ross Parke and colleagues observed parents as they interacted with their newborns. According to Mother Bodies, Father Bodies, here is what he found:
'Mothers and fathers showed patterns of striking similarity' when it came to interacting with their newborns; 'they touched, looked [at], vocalized, rocked and kissed their newborns equally.' Parke also found that fathers can be as responsive as mothers to infants' behavior and verbal cues. After assessing his own research and the larger body of literature on this topic, Parke has concluded that 'both men and women seem to be equally competent caregivers and exhibit high degrees of similarity as caregivers.'
3. Fathers typically engage their children in ways that are distinct from how mothers typically engage their children.
According to psychologist Rob Palkovitz, fathers "play a particularly important role in stimulating children's openness to the world in exciting, surprising, destabilizing, and encouraging them to take risks and to stand up for themselves." Fathers are more likely to throw their kids up in the air than mothers. When they play, they tend to "treat their daughters and especially their sons as worthy competitors." This is in contrast to mothers, who as one research team found, "tend to tip the playing field in the direction of children's needs and self-confidence."
Kline and Wilcox also note that while mothers do more of the disciplining (perhaps because they typically spend more time with children), when fathers do exercise discipline, they are more likely to "stick to a strict interpretation of family rules."
4. This distinctive paternal style of engagement with children can be good for children.
As Kline and Wilcox report, one study found that toddlers "are more likely to engage in novel activities, interact with strangers, and develop a spirit of independence at the urging of their fathers rather than their mothers."
Another study found that dads who spend lots of positive play time with their children have children who register the most popularity with their peers.
And all the firm discipline in which fathers tend to excel? It turns out that children are more likely to comply with dads' demands than with moms' demands.
5. Boys and girls need good fathers.
As Kline and Wilcox note, paternal involvement with children is linked to lower levels of delinquency and criminal activity adolescents, even after controlling for maternal involvement. The same goes for academic achievement. They point to one study that compared moms' and dads' contributions to children's academic achievement found that "fathers account for more of the variance" in children's outcomes than do mothers.
Another study, noted in the report, of more than 2,000 adolescents found that "girls' closeness with their fathers, but not their mothers, predicted whether or not girls transitioned into sexual activity."
Finally, psychologist Bruce Ellis and colleagues found that only 5 percent of teenage girls became pregnant if they were raised in a home with their father. By contrast, 35 percent of teenage girls became pregnant if their father left before they turned six.
6. Today's dads are spending more time with their kids than older generations of dads.
The total time that fathers spent in the presence of their children rose 240 percent from 73 minutes in 1975 to 248 minutes in 2003. During the same time, their primary time (one-on-one time) with children tripled, from an average of 14 minutes in 1975 to 42 minutes in 2003. (Though mothers still take the lead in the amount of total time spent with children, with an average of 387 minutes in 2003, and an average of 95 minutes of primary time in 2003.)
7. Strong couples make strong families make strong kids.
If involved and affectionate fathers are important, so is the father's relationship with the mother. As Mother Bodies, Father Bodies, summarizes the evidence, "studies consistently find that fathers and mothers who enjoy a strong pair bond with each other are more likely to be involved and affectionate caretakers of their children." For instance, one study found that 65 percent of young adults whose parents divorced had poor relationships with their fathers.
For aspiring fathers and experienced fathers, the new science of fatherhood is encouraging because it suggests that when it's time to become a parent, our bodies are wired for the task. But it's also sobering, because it reminds us of the privileged bond fathers enjoy with their children, and the high responsibility that that privilege places on fathers. As Yale psychiatrist Kyle Pruett put it, "We've come to understand that fathers don't mother and mothers don't father. Fathers can't really be replaced, in full, especially by somebody who doesn't feel like a father."