By Shirley Ransdell, Junior writer
Thursday, May 17, 2018

(NEW FRONTIER NEWS)- It’s intuitive for people to think that the male brain is masculine, and the female brain is feminine.

It then matches with the idea that estrogen would feminize a female brain, and testosterone would make a male brain.

Except that’s not the whole story. According to Scientific American, in mice its opposite of what you would think.

Estrogen masculinizes the rat brains, and in their article, they talk about an experiment in which they exposed the brains of female mice to estrogen, and they began exhibiting male behaviors.

Specifically, the female mice would mount other female mice and do pelvic thrusting behaviors.

What does mice behavior have to do with humans?

Well, a lot of the time mice are used for their connections to humans in a lab setting.

However, we don’t even have to use mice.

There is a lot of discussion on whether or not estrogen has a role in masculinizing the female brain.

One scientific paper that was written in 2018 was written by Puts and Motta-Mena and looks at what effect estrogen has on the female brain.

Their conclusion is that estrogen has little effect in masculinizing the female brain and behavior.

However, another article commented on their review of Puts and Motta-Mena.

This article was written by Luoto and Rantala, and they break down why Motta-Mena is incorrect, they do this by including different pieces of evidence from the article and breaking them down.

The first evidence discussed is that humans don’t have the same ways to transform testosterone into estrogen as rats do, so there is no way that estrogen can change the brain, but the brain can change testosterone into estrogen using a different transformer than rats.

The second evidence cannot be extended to females.

In the third line of evidence, he uses a sample size of two males which cannot be extended to all males.

These reasons make up the conclusion that we cannot accept that Motta-Mena’s paper is correct.

The opposing review is not the only one that refutes Motta-Mena’s conclusion.

Wu, and Shah’s paper on the subject finds that estrogen and testosterone work to masculine the brain in many species.

They say that estrogen sets up the masculinization, and testosterone makes up the extent to which they are masculine.

Wu et al also finds that transformation of testosterone into estrogen also important to show male territorial behaviors.

Another paper by Wu et al in the same journal also looks at mice again with the changes in brains due to estrogen.


David Biello. (January 2006). Female Hormone Key to Male Brain. Scientific American. USA.

Severi Luoto, Markus Rantala. (January 2018). On estrogenic masculinization of the human brain and behavior. ELSEVIER. USA.
Puts D, Motta-Mena NV. (September 2017). Is human brain masculinization estrogen receptor-mediated? Reply to Luoto and Rantala. NCBI. USA.
Melody Wu, Nirao Shah. (October 2010). Control of masculinization of the brain and behavior. NCBI.
Melody Wu, Devanand Manoli, Eleanor Fraser, Jennifer Coats, Jessica Tolkuhn, Shin-Ichiro Honda, Nobuhiro Harada, Nirao Shah. (October 2010). Estrogen masculinizes neural pathways and sex-specific behaviors. NCBI. USA.
Khatuna Gagnidze, Donald Pfaff. (October 2009). Sex on the Brain. Cell. USA.