Does Intelligence Really Come From Your Mom? Here’s What the Science Actually Says

You’ve probably seen the headline before: “Intelligence comes from your mother,” “Credit mom for your brain.”

According to scientists, the truth is far more nuanced and far more interesting. Research spanning decades suggests maternal genes play a significant role in cognitive development, but genetics alone never tells the full story. Intelligence emerges from a mix of biology, environment, and early relationships, and mothers often sit at the center of that equation.

Here’s what the science actually says.

Where the idea that intelligence comes from your mother started

According to The Independent, scientists have long observed that genes associated with cognitive function frequently appear on the X chromosome. Women carry two X chromosomes, while men carry one. This alone increases the likelihood that intelligence-related genes pass through the maternal line.

As Charlotte England reported for The Independent, researchers also explored the role of “conditioned” or “imprinted” genes. These genes behave differently depending on whether they come from the mother or the father. In some cases, genes linked to advanced cognitive functions activate only when inherited from the mother and deactivate when inherited from the father.

Early laboratory studies using genetically modified mice reinforced this theory. Mice with extra maternal genes developed larger brains and heads but smaller bodies. Mice with extra paternal genes showed the opposite pattern: larger bodies and smaller brains.

What animal studies reveal

Researchers examined where maternal and paternal genes expressed themselves in the brain. According to The Independent, paternal genes clustered in the limbic system, the region associated with instincts like aggression, sex, and hunger. Scientists did not find paternal gene expression in the cerebral cortex, the area responsible for reasoning, language, planning, and conscious thought.

Maternal genes appeared more frequently in the cerebral cortex. This discovery fueled the claim that intelligence originates primarily from mothers.

However, scientists consistently warned against drawing direct conclusions about human intelligence from mouse studies alone.

Human research adds critical context to the genetics of intelligence

To test whether these findings translated to humans, researchers in Glasgow conducted a long-term study involving 12,686 young people aged 14 to 22, followed annually beginning in 1994.

Even after controlling for education, race, and socioeconomic status, the strongest predictor of a child’s IQ remained the mother’s IQ.

Still, genetics explained only part of the story. Researchers estimated that about 40 to 60 percent of intelligence is hereditary. The rest depends on the environment.

That distinction matters.

What Washington University discovered about maternal IQ

A major study published in the Journal of Child Psychology and Psychiatry by researchers at Washington University School of Medicine examined the relationship between maternal IQ and children’s cognitive outcomes.

According to the study, maternal intellectual ability strongly predicted both children’s IQ and language skills at age 5. This held true for children born full term and for those born very preterm.

After adjusting for poverty, family structure, and medical risk, maternal IQ explained nearly 19 percent of the variation in children’s IQ scores. Language outcomes followed a similar pattern.

Notably, the researchers emphasized that maternal IQ functioned as both a genetic factor and a contextual one. Intellectual ability shapes access to resources, learning opportunities, and daily interactions.

Why early bonding influences intelligence

Genetics alone never operates in isolation.

According to research from the University of Washington, emotional support during early childhood plays a measurable role in brain development. Children whose mothers provided consistent emotional support had hippocampi that were about 10 percent larger by age 13 than those of children with emotionally distant caregivers.

The hippocampus governs memory, learning, and stress regulation.

As Dr. Joan Luby later clarified, this effect reflected a psychosocial process rather than a genetic one, and it related to caregiving behavior rather than to gender itself.

Scientists push back on oversimplified genetics of intelligence

The popular claim that intelligence comes solely from mothers overshoots the evidence.

Many headlines traced back to blog posts that misrepresented decades-old studies. Several mouse embryo experiments focused on genomic imprinting rather than intelligence. Brain tissue appeared in some studies, but researchers never defined intelligence or measured cognitive ability directly.

Dr. James Curley, a neuroscience professor at Columbia University, told Science Says that gene expression in the cerebral cortex should not serve as a proxy for intelligence. These genes contribute to brain development and neural circuits, but intelligence involves thousands of interacting genes.

Other findings complicate the narrative even further. Women with Turner syndrome showed thicker cortical regions when their X chromosome originated from their father, suggesting that paternal genes also influence brain structure.

Where fathers fit

Most studies focus on maternal IQ because mothers historically served as primary caregivers and because data availability skewed in that direction. Several studies did not measure paternal IQ at all. This absence makes it impossible to claim that fathers play no genetic role in intelligence. Intelligence remains a highly polygenic trait, meaning hundreds or thousands of genes contribute small effects.

As Cambridge University Press notes in its chapter on the genetic bases of intelligence, genome-wide association studies have identified around 150 genes linked to intelligence. Still, epigenetic mechanisms and environmental influences continue to complicate heritability estimates.

The takeaway

Yes, maternal genes matter, but the X chromosome does too. Maternal IQ predicts cognitive outcomes across multiple studies. But intelligence never flows from a single source.

According to researchers across institutions, intelligence develops through genetics, early emotional security, nutrition, education, and stimulation. Mothers often influence many of these factors, both biologically and socially. Fathers influence them too.

In other words, intelligence grows in relationship, context, and care. And science agrees on one thing. Reducing intelligence to a single parent makes for a catchy headline, but it misses the real story.