New Study Reveals A Man’s Brain Changes When He Becomes A Father

According to a relatively new study, having a baby changes a man’s brain.

“Dad brain” is a real thing, and a new study is breaking down how a man’s brain goes through hormonal changes once they have a child. The new study, published in the journal Cerebral Cortex, outlined how a man becoming a father transforms their brain: it literally shrinks. Slightly.

“Across the board, we found similar reductions in gray matter, sort of suggesting that the brain was becoming more streamlined and possibly more efficient over that transition to first-time parenthood in the fathers,” said Darby Saxbe, Ph.D., a professor of psychology at the University of Southern California, who was also one of the lead researchers in the study, Fatherly reports.

In addition, fathers undergo other changes like their testosterone levels dropping and their bodies producing oxytocin and prolactin, which are considered “feel good” or “nurturing hormones.”

The study analyzed the brains of 57 men who were, on average, in their mid-30s. Twenty expecting fathers were from the U.S., 20 were from Spain, and 17 were childless men from Spain. Some had their brains scanned before their partners got pregnant and about three months after their partners gave birth.

“In both samples of fathers, we found that there was volume reduction in the cortical area of the brain,” Saxbe says, Fatherly reports. “Much like at other critical windows in the lifespan, when we consolidate and prune, the brain becomes more streamlined or more efficient.” While the changes in men’s brains are similar to what happens for mothers, expecting women also experience changes in their subcortical brain areas, which are responsible for instinct, emotion, and fear.

“The cortex is the latest-evolving part of the brain that is involved in attention, planning, and executive functioning and is more unique to humans,” Saxbe told USC News. “The subcortical regions (below the cortex) are the more basic brain structures that you see in animals, involved in reward, threat, and salience detection. In moms we see both subcortical and cortical changes … in dads we just saw cortical changes. It’s too soon to speculate with such a small sample but it might suggest more higher-order processing involved in fatherhood specifically.”