03/15/2025 / By Olivia Cook
For years, scientists have been searching for answers to a long-standing mystery: Why is autism spectrum disorder (ASD) more common in boys (about four times more) than in girls? While genetics play a major role, emerging research suggests that prenatal hormones – and even the placenta – could be key players in shaping autism risk. A new study published in Frontiers in Endocrinology in May 2023 explores this fascinating connection, offering fresh insights into how genes, hormones and early development interact.
Most people think of the placenta as a simple filter between a mother and her baby, but it is actually an active organ that helps guide fetal development. It regulates hormones, influences gene expression (controls how genes work) and even impacts or helps shape fetal brain development.
This study found that genes linked to autism show different activity levels in male and female placentas. Since boys have only one X chromosome while girls have two, they may have fewer “backup copies” of certain important genes. This could make male fetuses more vulnerable to developmental conditions like autism.
Hormones, like testosterone and estrogen, which help guide brain and physical development, play an important role even before birth. Research has shown that some autistic individuals had higher prenatal levels of certain hormones, including estrogen, which are mainly produced by the placenta. But how do genes come into play?
The study found that several autism-related genes, including KDM5C and DDX3X, are involved in hormone activity and brain development. Mutations in these genes are also linked to rare conditions that affect development:
One of the study’s most unexpected discoveries was that men with genes linked to autism were less likely to develop male-pattern baldness or androgenic alopecia (hair loss).
At first, this might seem confusing. Since testosterone is known to contribute to hair loss, scientists expected autistic men (who often have higher testosterone levels) to lose hair more often. However, autism has also been linked to higher levels of estrogen, which might counteract testosterone’s effects on hair follicles.
While no studies have directly examined whether autistic men are less likely to go bald, this genetic link suggests that autism-related hormonal differences could affect more than just the brain.
Previous research has shown that autistic individuals (both male and female) tend to go through puberty earlier than their peers. Scientists aren’t exactly sure why, but it is possible that the same hormonal factors affecting brain development in autism also speed up overall physical maturation.
Early puberty has been linked to higher risks of anxiety, depression and other mental health challenges – conditions that are also more common in autistic individuals. Understanding these links could help researchers to develop better ways to support both the physical and emotional health of autistic people.
These findings paint a complex picture of autism, where genetics, prenatal hormones and early development are deeply connected. The study reinforces the idea that the placenta is not just a passive organ but a critical regulator of brain development – one that may contribute to the differences in autism prevalence between males and females.
However, it is important to remember that genetic links do not necessarily mean direct causation. Many factors contribute to autism, including environmental influences, nutritional factors and social dynamics like gender norms and gender-based diagnostic biases, which may affect why fewer girls are diagnosed.
The findings provide insights into why autism is more common in males, suggesting that sex-specific placental functions might mediate the genetic risk.
Watch this video to learn how prenatal factors affect autism and other conditions.
This video is from the Daily Videos channel on Brighteon.com.
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Tagged Under:
autism, autism research, autism-related genes, early puberty, estrogen, fetal brain development, genes, genetics, hormones, placental health, testosterone
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