Autism, genes and hormones: How the placenta may hold clues to autism's puzzle
By oliviacook // 2025-03-15
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  • Autism is more common in boys than girls, and new research suggests that prenatal hormones and the placenta may influence genetic risk factors for autism.
  • The placenta actively regulates hormone levels and gene expression, with male and female placentas functioning differently, potentially contributing to autism's sex differences.
  • Autism-related genes interact with prenatal steroid hormones, like estrogen and testosterone, affecting early brain development and potentially influencing autism risk.
  • The study found unexpected connections between autism and traits like male-pattern baldness (lower risk in autistic men) and earlier puberty onset in autistic girls.
  • Understanding how genes, hormones and the placenta interact could lead to new insights into autism, including interventions and better support for autistic individuals.
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.

Placenta: More than just a baby's life support

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 and 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:
  • Klinefelter syndrome happens when a male is born with an extra X chromosome, which can affect learning and development.
  • Cornelia de Lange syndrome is a genetic disorder that can lead to developmental delays and physical differences, some of which overlap with autism traits.

Baldness and autism

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.

Puberty and autism

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.

Why is this important?

The findings provide insights into why autism is more common in males, suggesting that sex-specific placental functions might mediate the genetic risk.
  • Hormonal influences. The study highlights the potential role of steroid hormones (testosterone and estrogen) in autism, opening new avenues for research and scientific inquiry into hormonal therapies or interventions.
  • Placental health. The findings underscore the importance of placental health during pregnancy, suggesting that factors affecting placental function could influence neurodevelopmental outcomes.
Watch this video to learn how prenatal factors affect autism and other conditions. This video is from the Daily Videos channel on Brighteon.com.

More related stories:

Autism begins during pregnancy, may be caused by mercury in dental amalgam and thimerosal in flu shots, warns science paper. DISTURBING: Scientists use lasers to discover baby teeth of children with AUTISM contain shockingly high levels of HEAVY METAL TOXINS. Autism symptoms may be reduced by therapeutic scalp acupuncture, researchers find.

Sources include:

FrontiersIn.org NHS.uk MedlinePlus.gov Brighteon.com
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