Decoding Boys and Girls Brain Differences through Neuroscience

Breaking the Gender Code: Decoding Boys and Girls Brain Differences through Neuroscience

Is there a difference in brain development between girls and boys?

Boys’ and girls’ brains are different. Let me illustrate it with a story. It was a lovely sunny morning, and my mom had just finished hanging up a load of laundry on the clothesline strung up in the yard along the side of the house. I had just sat down to enjoy a cup of tea with my favorite stuffed animal Teddy when my brother six-year-old brother Tom, burst out of the back door and raced past the mulberry bush and around the walnut tree.

Ted, age three, was in hot pursuit, yelling,

It was my idea; I thought of it first,  as they tore around the corner of the house. Ted, determined to catch his older brother, who was in the lead, took a shortcut through the Teddy Bear’s tea party that I had diligently set up, sending Teddy and my mudpie teacakes for the party flying. I burst into loud wailing. You ruined my party, I cried. With barely a glance back, both brothers continued to race toward the coveted prize. A red wagon was sitting at the bottom of the hill behind our house. The boy that got there last would have to pull the wagon up the hill. Then both boys would leap in and ride the wagon down the hill, whooping and hollering with glee.

However, on this day, that brief backward glance at their furious sister meant they didn’t see the clothes hanging on the clothesline directly in their path. They didn’t see a load of washing my mom had just hung out to dry and Dad’s pair of jeans that was between them and the coveted red Radio Flyer wagon. Tom ran right into Dad’s pair of jeans hanging on the line. In hot pursuit, Ted ran into Tom’s back, sending him and the pair of jeans to the ground. As Tom went down, Ted landed on top of Tom, and both boys forgot all thoughts of the red wagon as they rolled around on the ground, trading insults and punches with each other.

Mom came running and separated both boys, marched them back to the house, and the red wagon mysteriously disappeared for several weeks.

You don’t have to be a brain scientist to realize that little boys love action, activity, and adventure.

Breaking the Gender Code: Decoding Boys and Girls Brain Differences through Neuroscience

Brain Differences in Boys and Girls

When did you last watch a group of preschool children play at the park or playground? The boys were likely in constant motion as they ran, jumped, climbed, and swung from anything that would support their weight and may have even swung their fists at each other.

The girls, however, may have been off by themselves, preferring to play in a group, taking turns, or cooperating with the other girls. It’s no accident they are this way. Scientists and psychologists thought this stereotypical behavior was due to socialization. Now, we know that the motivation for movement in boys and the cooperation and cuddling or mothering in girls are hardwired into their fetal brains before birth.


The Gender Differences In Behavior Start Before Birth​

Come with me as we take a peak into the brain of a developing fetus. What we see in the male fetus is that at about eight weeks of gestation, the tiny testicles of the developing male fetus begin to pump out testosterone.

The testosterone floods the brain and turns on the genes that contain the blueprint for these critical movement circuits. As we watch these genes turn on, we see the construction of the circuits for the urge to track and chase moving objects, to hit things, to test their strength, and to fight off rivals, aka their siblings, especially a brother as a brother is more likely to engage in and even enjoy these tests of strength and the constant movement that’s involved. The rivals change as they age, but the urge to defend their territory will remain. In addition to turning on genes, testosterone also kills off cells in the communication centers of their brains and grows more cells in the sex and aggression centers of their brain. 


My brothers Ted and Tom weren’t taught to be movement and action-oriented; they weren’t taught to fight off rivals; they were following their biological wiring and instructions of these action circuits that were hardwired prenatally.

The Secret to Healthy Physical Brain Development

When the difference start?

The male and female brains look the same until eight weeks of fetal development. Female is the default gender setting of nature. If there is no surge of testosterone, then the female infant brain continues to grow unperturbed, and we see her brain begin to construct more neurocircuits in the area of the brain for communication. Observation and processing emotions. How might these additional neurocircuits affect her? Because of her more extensive communication, observation, and emotion processing centers, she will grow up to be more talkative than her brother. 

She will also use more nonverbal and verbal communication in social situations than he will.


When my daughter was an infant, I was worried that there was something wrong with her vision. She would stare long and hard at my face as I held, nursed, and cuddled her. But as soon as I put her in her crib, she’d cry and look heartbrokenly in my direction.

Even the mobile hanging above her crib didn’t calm her down. Because I had a son first, I expected her to be more like him. I didn’t understand that infant girls’ brains are hardwired to study faces. They love to make eye contact and mirror the emotions they see in our faces.  

When I brought her older brother home from the hospital and put him in his crib if he started to cry, I would turn on his mobile of shapes, and he would instantly calm down and stare at them as they rotated round and round. He wanted to look at everything else – his mobile. The lava lamp on the dresser beside his crib and even the geometric patterns decorating the walls of his room.


No one had taught him to track their movements; he just did. I didn’t realize back then that boys aren’t conditioned by their environment to track moving objects, but they come biologically prewired to track moving objects. They are wired to pay more attention to movement, the edges and angles of things, and geometric patterns from the get-go. It results from part of their brain being marinated in testosterone and other male sex hormones before birth.   

Brain development in kids

Child development experts used to think that mutual gazing was necessary for proper bonding of the infant with their caregiver. These early studies were based on girls, not boys. Boys experience the testosterone surge that shrinks their centers for communication, observation, and processing of emotions. Over the first three months of life, a baby girl’s skills in eye contact and mutual facial gazing will increase by over 400 percent. At the same time, these skills in an infant boy will not increase. By the time boys and girls are six months old, boys will be breaking eye contact and looking away from faces much more than girls. Girls will look at faces longer and make eye contact with just about everyone.

There is nothing wrong with the boys; how they are wired means their male brain finds moving objects like remote-controlled cars more attractive than faces.

Baby Girls are born with an interest in emotional expression. They make meaning about themselves from a touch, a look, and the reactions of the people they contact. These are key cues they use to discover whether they are lovable, worthy, or simply annoying. When a little girl sees an expressionless face turn toward her, she interprets it to mean she isn’t doing something right. She will try their best to get the reaction she expected but didn’t get.

You can imagine the negative effect this has on the development of a little girl’s sense of self if her mother is depressed and has an unresponsive, flat face or even one that has had excessive Botox injections. A nonexpressive face may be confusing to a little girl. She may decide and believe her mother’s lack of facial expressions means she isn’t loved and valued by her mother. She may focus on more responsive faces because she is hardwired to seek connection.

While the brains of an infant boy or girl may appear to be the same, under the microscope or an FMRI scan, there are complex and widespread differences. When we look at neurocircuitry, there are some profound differences in how they are wired due to the influence of their sex hormones. Two notable differences are boys are programmed and wired for movement and motion. They come biologically prewired to track moving objects. They pay more attention to the edges and angles of objects and geometric patterns from the get-go.

Girls’ brains have 11 percent more neurons and more neurocircuits in the area of the brain for communication, observation, processing, and remembering emotional events. Because of her more extensive communication, observation, and emotion processing center emotions, girls will grow up to be more talkative than their brothers. They will also use more nonverbal and verbal communication forms in social situations.

Girls’ brain circuits for observation will push them to gather meaning for faces and tones of voices. 

She will be able to understand the social approval or disapproval of others at a very early age. Like we can’t hear sounds that our pets can hear. Girls can hear the emotional nuances of tone in the human voice better than boys. This drive to connect and engage socially teaches a girl about her sense of self. Whether she is listened to or not, it will tell her if she is being taken seriously and will create her sense of self as being successful. If she doesn’t connect and her constant chatter is ignored, her sense of self may be a belief that she isn’t successful. Listening attentively to our daughters when they chatter helps them develop more confidence.

These are a few important differences we see in girls vs. boys.