10/19/2025
As men age, their s***m accumulate more genetic mutations, which can increase the risk of harmful effects in offspring. This phenomenon occurs because s***m-producing cells, known as s***matogonia, undergo continuous division throughout a man's life.
Each division introduces a chance for DNA replication errors, leading to mutations. Unlike women, who have a fixed number of eggs from birth, men produce s***m continuously, and the number of cell divisions increases with age, amplifying mutation accumulation.
Studies show that older fathers (typically over 40) pass on more de novo mutations—new genetic changes not inherited from either parent—to their children. On average, a 20-year-old father passes about 25 mutations, while a 40-year-old may pass around 65.
These mutations arise in the s***m's DNA and can affect genes critical for development or health.While most mutations are benign, some can be harmful, potentially increasing the risk of conditions like autism, schizophrenia, or congenital disorders in children.
For example, mutations in genes like FGFR3 are linked to rare disorders such as achondroplasia. The risk, though small, grows with paternal age.Lifestyle factors like smoking or environmental exposures can exacerbate mutation rates, but age remains the primary driver.
While the overall risk of harmful outcomes is low, the trend underscores the importance of considering paternal age in reproductive health discussions, alongside maternal age, for informed family planning.