HERE’S A SENTENCE guaranteed to start a family argument over dinner:
“Children get their intelligence from their mothers.”
Give it a few seconds and watch every father at the table sit up straighter.
Relax. Nobody’s insulting Dad. This is simply genetics doing what genetics often does — quietly dismantling our assumptions while everyone argues about something else.
Let’s start with the straightforward part: gender.
Every human child receives 23 chromosomes from the mother and 23 from the father. But when it comes to whether a baby is male or female, the father holds the deciding card.
Mothers always contribute an X chromosome. No variation there. Every egg carries one.
Fathers produce sperm carrying either an X or a Y chromosome. If the sperm delivers an X, the baby becomes XX — female. If it delivers a Y, the baby becomes XY — male.
In other words, Dad determines the baby’s biological sex.
So, the next time someone in the family says, “We were hoping for a boy,” the polite scientific response is: take it up with the father’s chromosomes.
‘Studies on brain development also suggest that maternal genes play a major role in shaping the cerebral cortex, the part of the brain responsible for reasoning, language, and complex thought.’
GENOMIC IMPRINT
Now let’s talk about something more interesting — intelligence.
Many genes associated with cognitive ability are located on the X chromosome. That matters because mothers carry two X chromosomes, while fathers have only one.
Some genes are also preferentially expressed, a phenomenon known as genomic imprinting. In simple terms, certain genes from one parent are more likely to be “turned on,” while the corresponding gene from the other parent stays quiet.
Research on these patterns suggests that genes linked to higher cognitive function are more often expressed when they come from the maternal X chromosome.
It’s not the whole story of intelligence — not even close — but it’s an intriguing piece of it.
NOT A SINGLE GENE
Studies on brain development also suggest that maternal genes play a major role in shaping the cerebral cortex, the part of the brain responsible for reasoning, language, and complex thought.
Paternal genes appear to influence other systems more strongly — including growth, metabolism, and instinct-driven behaviors.
If that sounds suspiciously like the difference between organizing the family calendar and asking “what’s for dinner,” feel free to draw your own conclusions.
But let’s slow down before anyone declares mothers the sole owners of brainpower.
Intelligence is not a single gene.
It’s the result of hundreds — possibly thousands — of genes interacting with each other and with the environment a child grows up in. Nutrition matters.
Education matters. Curiosity matters. Sleep matters.
BIOLOGICAL ROLE
A child raised with encouragement and stimulation will usually outperform a child raised on neglect and algorithm-fed nonsense, no matter which chromosome carried the original blueprint.
Genes may set the stage. Life writes most of the script.
Still, the maternal contribution to cognitive development is real enough to acknowledge — especially during Women’s Month.
For much of history, women’s intellectual influence was minimized while their biological role was treated as purely mechanical. The mother carried the child. The father carried the legacy.
Modern genetics suggests something more balanced.
Yes, the father determines whether the baby is a boy or a girl.
But the mother provides a double set of X-linked instructions that help shape the brain doing the thinking.
Put another way: Dad decides the packaging.
Mom contributes a good portion of the processor.
HALF OF THE ENVIRONMENT
Of course fathers still contribute half the DNA — and often half the environment that shapes a child’s mind. Bedtime stories, curiosity, patience, conversation. Those things build intelligence too.
Still, it feels appropriate to say this during Women’s Month.
Behind every sharp, curious child is usually a mother whose DNA — and persistence — helped build the operating system.
And if the kid grows up stubborn, loud, and absolutely convinced they’re always right?
Well.
We’ll let Dad take that one.
The Certified Prick – just the messenger—feel free to argue amongst yourselves.