Testosterone levels show a significant peak during a critical developmental window when the brain is forming, influencing the development of male versus female brains.

“So there are the critical period in development, You've got the period where testosterone is being produced, um in the fetus and within that there are certain developmental periods where different parts of the brain and body are receptive to testosterone's actions. And this is um there are different we know from um non-human primates that there are different per critical periods for say development of the genitalia other parts of the reproductive system and potentially for sexual and aggressive behavior separately.”

“So, >> testosterone, you have this real peak difference in testosterone during a critical window of development when the brain is developing. And so, you have a female brain that is developing in the absence of testosterone. And you have”

“It's it's more the XX brain is developing in the absence of testosterone. The XY brain is developing in the presence of high amounts of testosterone.”