A new study published in the biology of sex differences has revealed that the structural differences between the male and female brain are present from birth and remain relatively unchanged during the first month of life, highlighting the significant role of prenatal biological factors in the formation of early development of the brain.
Research, carried out by scientists from the University of Cambridge as part of the human development project project, analyzed the brain scans of 514 healthy newborns – 278 boys and 236 girls – all in the first 28 days of life.
Using magnetic resonance imaging (MRI), the researchers found that male infants had larger overall brain volumes, a scheme that aligns the results in older children and adults.
However, after adjusting the total size of the brain, female infants have more gray matter, the part of the brain responsible for information processing, while male infants had more white substance, which facilitates communication between brain regions.
The main author Yumnah Khan, a doctoral student at the University of Cambridge, said that the results challenged long -standing hypotheses that such differences based on sex in the brain are largely the result of social or environmental influences.
“Several differences in on average sex in the brain are already present from birth, indicating that prenatal factors play an important role in initiating sexual differences in the brain,” Khan told Psypost.
Explore structural differences in the brain
MRI analyzes have revealed specific brain regions where the sexes differ. Infants had relatively larger volumes in the Callosum corpus, the bridge between brain hemispheres and the parahippocampal gyrus, linked to memory.
Meanwhile, male infants showed larger volumes in the medial and lower temporal gyri, the areas associated with visual and auditory treatment.
In particular, these differences remained stable throughout the first month of life, suggesting that they were established before birth rather than shaped by early postnatal experiences.
“We found it very interesting that several of the sexual differences that have been observed before in older children and adults were already present at birth,” said Khan. “This emphasizes that these differences have been present since the very beginning of life and probably emerge prenatal.”
Implications for neurodevelopmental research
The results have important implications to understand why certain neurological and psychiatric conditions – such as autism, ADHD and depression – occur more frequently or present differently in men and women. Researchers say that these conditions can be linked to early structural differences in the brain, offering a potential path for previous identification and targeted interventions.
Khan stressed that the interest in sexual differences is not only academic, but also practically significant.
“A better understanding of sexual differences, their underlying causes and the chronology of their emergence may explain why certain disorders affect men and women differently.
Caution against excessive over-management
Despite the results, the researchers took care to warn me against the over-interpretation of the results. The differences observed are average differences between large groups and do not suggest that male and female brains are fundamentally or universally different.
“It is important not to overestimate or exaggerate the differences,” said Khan. “The brain is not” sexually dimorphic “like the reproductive organs. The brains of men and women are more similar than they are different. ”
The study has not studied if the structural differences observed result in behavioral or cognitive differences, and it has not explored precise causes – whether genetic, hormonal or environmental – of these first brain differences.
“There is still much more to discover,” said Khan. “We must now determine whether these structural differences are linked to behavior, cognition or future development results. Understanding the origins and implications of these differences is the next critical step. ”
This research marks one of the most detailed investigations in sexual differences in the neonatal brain, offering a fundamental understanding of the way in which male and female brains are starting to diverge – if not slightly – of the very first days of life. This also adds to all evidence that biological sex plays a role in the development of the brain of the early stages, long before social and cultural influences settle.
