Jan 29, 2025 07:00:00

Research shows that men's sperm contain traces of stress experienced during childhood

It is known that stress and trauma experienced in childhood can have long-lasting effects on adult

health, economic status , pain and loneliness in later life , etc. A study conducted by researchers in Finland and Denmark revealed that traces of the stress experienced in men's childhood are also found in their sperm.

Exposure to childhood maltreatment is associated with specific epigenetic patterns in sperm | Molecular Psychiatry
https://www.nature.com/articles/s41380-024-02872-3

Sperm cells carry traces of childhood stress, epigenetic study finds | Live Science
https://www.livescience.com/health/fertility-pregnancy-birth/sperm-cells-carry-traces-of-childhood-stress-epigenetic-study-finds

The study looked at epigenetics in men's sperm - a field that studies changes in how DNA is read, rather than changes in the DNA itself, which is the blueprint for making the body's proteins and molecules.

It has been suggested that humans leave epigenetic changes in their DNA, such as 'which genes are expressed ' in response to experiences and the environment, which may change gene activity. 'Epigenetics basically tells us which genes are active,' said Dr. Jetro Tuulari , lead author of the paper and associate professor at the University of Turku in Finland. 'Understanding genes and inheritance through DNA is one of the most important parts of understanding biology.'

The research team recruited subjects through the FinnBrain Birth Cohort project, which examines environmental and genetic factors that affect child development. They then measured childhood stress using the Trauma and Distress Scale (TADS), a questionnaire that asks about memories of emotional and physical neglect and abuse, or sexual abuse. Sperm was collected from a total of 58 subjects, including those who remembered little childhood stress and had low TADS scores (TADS scores of 0 to 10) and those who remembered many traumatic events and had high TADS scores (TADS scores of 39 or higher).

The research team analyzed sperm collected from the subjects and investigated '

DNA methylation ' and ' small noncoding RNA ' related to epigenetics. DNA methylation is a chemical reaction that adds methyl group modifications to bases in DNA, which changes the way genes are read. On the other hand, small noncoding RNA interferes with the reading of RNA involved in protein synthesis based on the genetic information in DNA, and has a similar effect on heredity.

The researchers found that sperm from men with higher TADS scores had different epigenetic changes than men with lower scores, even when they took into account other factors related to epigenetics, such as drinking and smoking, suggesting that early life stress influences sperm epigenetics.

Specifically, the sperm of subjects with high TADS scores showed a different expression of a non-coding RNA called 'has-mir-34c-5p,' which is known to affect the brain during early mouse development , compared to subjects with low TADS scores. Furthermore, the DNA methylation profiles of two genes, ' CRTC1 ' and ' GBX2 ,' were also different between subjects with high and low TADS scores.

The stressful events that occurred in the high TADS subjects' lives continued to affect epigenetic changes in their sperm even decades later. These epigenetic changes do not necessarily translate to offspring, but laboratory animal models, including nematodes and mice, have shown that epigenetic changes can be passed on from parent to offspring.

Tuulari said it's too early to draw any conclusions about the impact of early childhood stress on children's health, and added that it's not yet clear what the ultimate impact of the epigenetic changes observed might be.