How your body and brain change when you become a dad


There’s a lot to be said about how motherhood changes women. And (thankfully!), we’re seeing a lot more credit being given for the monumental physical, mental, and emotional changes women undergo when they experience pregnancy and motherhood. But there’s another very important person undergoing their own metamorphosis through parenthood: dads

While fathers don’t experience the same tell-tale physical implications of parenthood as mothers do, an abundance of research has discovered that men’s bodies transform when they become a parent. Specifically, significant shifts are happening below the surface with their brain and hormone levels. 

Talking about the mental and emotional changes in men after they become fathers, Ana Sokolovic, M.S. Clinical Psychology and licensed psychotherapist and coach from Parenting Pod says, “The changes differ depending on the father’s level of preparedness to take on such responsibility and the level of investment in parenting. Some ‌changes include an Increased level of responsibility for providing for a family. Gentleness—their non-verbal expression of affection becomes more gentle. A perceived loss of freedom—though they may have been on some level prepared that the family plans will have to bend towards the child’s needs, there is always some resistance to fully accepting this change.”

A drop in testosterone

A drop in testosterone is one of the primary hormonal changes men experience after becoming fathers. A survey conducted in 2005 and 2009 of 600 men found that new fathers showed a 26% drop in morning testosterone levels and a 34% decrease in evening testosterone levels, compared with single nonfathers, whose morning and evening testosterone went down by 12% and 14%, respectively. 

Dad changing his baby's diaper

The lowest levels were found in men with children under one month and those who spent the most time with their children. Why the big drop? Researchers have found that lower levels of testosterone tend to contribute to higher levels of empathy, sensitivity, and a desire to be more involved in caring for the child. 

In contrast, men with higher testosterone levels have been shown to be less likely to respond to a crying infant. They have less patience in high-anxiety situations (like a baby meltdown, for example). 

The truly remarkable thing is the effect behavior had on the results. When new fathers have a deeper level of engagement with their children, engaging in playing, skin-to-skin contact, and other bonding activities, they see the most significant hormonal response. And those increases, in turn, promote a brain with more desire and likelihood to engage with their child again. 

In short, hands-on parenting in dads begets more hands-on parenting!

Hormonal changes that promote a deeper bond

Of course, there’s more to becoming an emotionally connected father than simply a drop in testosterone. 

Research has also shown that men tend to see an increase in the hormone estradiol (the primary form of estrogen) and prolactin (often called the “mom hormone” because it can promote lactation) in new fathers. As a result, there’s an increased sensitivity to the baby’s cries, especially when dads are involved in caregiving from the start. 

But while mothers start experiencing hormonal changes virtually from the moment of conception that can help them to bond with their baby, research has shown that dads experience the strongest shifts once they actually meet their little one. 

In a 2010 study called “Oxytocin and the Development of Parenting in Humans,” researchers evaluated 160 first-time parents’ oxytocin levels (also called the “love hormone”) at six weeks and six months after the birth of their baby. The results? Not only did dads experience an increase in oxytocin, but their levels were the same as the mothers’. 

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Dad playing with his baby

The study also showed that parenting style was one of the biggest factors in hormone levels, with fathers experiencing the highest levels who regularly engaged in more stimulatory contact, encouragement of exploration, and direction of infant attention to objects. 

In short, the more hands-on the parenting, the higher the oxytocin level.

Your brain on fatherhood

And there are physical changes at play, too. A 2014 study examined 16 new dads in the first few weeks after becoming fathers and then again between 12 to 16 weeks. 

The study found that physical changes also took place in the male brain, including an increase in gray and white matter in the areas of the brain responsible for empathy, attachment, and nurturing. In animal studies, these brain areas have been shown to be extremely important in the development of paternal behaviors and are similar to those found in mothers. 

In short, these neurons exist primarily for and because of the new child. 

Another study in 2014 also examined the effect of parenthood on heterosexual, primary-caregiving mothers, heterosexual secondary-caregiving fathers, and homosexual primary-caregiving fathers. The results found that mothers and fathers who acted as the primary caregiver experienced activation in the same areas that are linked to emotional processing and social understanding. Among all the fathers, time spent in direct child care seemed to be the biggest factor in determining activation in these areas.

Unlike mothers, a father’s emotional and mental changes do not appear to be automatically triggered by parenthood. Rather, the biggest shifts (and the deepest attachments) seem to come as a result of behavior and a mindset focused on involvement in caring for the child. 

Ana advises that to prepare for the way fatherhood changes men, “Talk to your partner. Discuss the expectations of parenting. Talk about the level of support you both require. Talk about the things you fear. Do not idolize parenthood. It is completely normal to be afraid of losing aspects of your life pre-parenthood. Talk to other fathers. Ask them to share their most valuable advice.”

Essentially, the quicker a father sees himself as playing a pivotal role in caring for the child, the more profound and long-lasting the results seem to be, which is good news for dads looking to have a more active role in raising their children! By engaging early and consistently, they find more joy in fatherhood―and their partners and children also reap the benefits.

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