Testosterone is a hormone that is produced by the testicles in males and the ovaries in females. While it is more commonly associated with males, both sexes produce testosterone in varying amounts.

On average, males produce 10 to 20 times more testosterone than females, and it plays a key role in male sexual development. However, high levels of testosterone during fetal development can have a significant impact on the developing fetus.

What is Testosterone?

Testosterone is a hormone that is responsible for the development of male sex organs, including the penis, testicles, and prostate gland. In females, testosterone is produced by the ovaries, but in much smaller quantities than males.

Testosterone also plays a role in sperm production, muscle and bone mass, and the distribution of body hair and fat.

Testosterone levels in males are highest during puberty and gradually decline after age 30. In women, testosterone levels fluctuate throughout the menstrual cycle and decline after menopause.

The Role of Testosterone in Fetal Development

Testosterone plays a key role in male fetal sexual development. During the first few weeks of fetal development, the fetus begins to develop what will eventually become the male reproductive system.

Testosterone is produced by the fetal testes and signals the development of the penis and scrotum.

Testosterone also plays a role in the development of the female reproductive system.

In females, small amounts of testosterone are produced by the ovaries and are converted to estrogen, which is necessary for the development of the female reproductive system.

High Testosterone Levels During Fetal Development

While testosterone is necessary for normal fetal development, high levels of testosterone during fetal development can have negative effects on the developing fetus.

Some studies have suggested that high levels of testosterone in female fetuses may increase the risk of developing polycystic ovarian syndrome (PCOS), a condition that can cause infertility, irregular periods, and other symptoms.

In males, high levels of testosterone during fetal development may increase the risk of developing testicular cancer later in life.

Some studies have also suggested a link between high levels of testosterone in male fetuses and an increased risk of autism spectrum disorders.

The Effects of Testosterone on Brain Development

Testosterone can also have an impact on brain development. In males, testosterone is responsible for the development of male-typical brain structure and function.

This includes a larger amygdala, which has been linked to aggressive behavior, and a smaller corpus callosum, which may contribute to differences in cognitive function between males and females.

Research has also suggested that prenatal exposure to high levels of testosterone may be linked to an increased risk of behavioral and cognitive problems later in life.

For example, a 2010 study found that girls who were exposed to high levels of testosterone in utero were more likely to exhibit aggressive behavior than girls who had lower levels of exposure.

Conclusion

While testosterone is necessary for normal fetal development, high levels of testosterone during fetal development can have negative effects on the developing fetus.

These effects can include an increased risk of developing conditions such as PCOS and testicular cancer, as well as an increased risk of autism spectrum disorders and behavioral and cognitive problems later in life.