Immune Cells: Do They Affect Our Sexual Behaviour?

What determines sexual behavior? Furthermore, to what extent are immune cells and learned factors relevant?
Immune Cells: Do They Affect Our Sexual Behaviour?
Gema Sánchez Cuevas

Reviewed and approved by the psychologist Gema Sánchez Cuevas.

Last update: 21 December, 2022

Are we typically ‘wired’ to act in a male or female way when it comes to sexual behavior? Do biological factors determine our social behavior? How much of this is learned behavior? As a matter of fact, according to a recent study, immune cells (mast cells) influence our sexual behavior.

The study observed changes in a set of immune cells that shape sexual behavior. The focus of the study was how mast cells, a certain type of immune cell, influence our sexual behavior. In fact, do they cause us to act in a more ‘masculine’ or ‘feminine’ way?

The study found that immune cells, often ignored as modulating variables, seem to play an important role in determining whether the sexual behavior of an animal will be more typical of a man or a woman. Furthermore, the researchers at Ohio State University, where this study was conducted and which was published in The Journal of Neuroscience, have found a surprising new explanation for how young brains are shaped toward future sexual behavior.

Are we ‘wired’ for certain sexual behavior?

For many years, researchers have provided evidence that, when it comes to humans, sexual behavior is difficult to classify.  As a matter of fact, it’s difficult to label one type of behavior as ‘male’ or ‘female’. Furthermore, many recent studies suggest that, without our knowledge, subtle characteristics of our body can influence our behavior.

The new research studies the role that a particular type of immune cell ( a mast cell) plays in the development of sexual behavior. The researchers conducted their studies with rats. They analyzed males with inactive mast cells and females with active ones. They also looked at the preoptic region of the brain, in the hypothalamus. This contributes to the regulation of sexual behavior.

Immune cells and their role in sexual behavior.

Kathryn Lenz is an assistant professor of psychology and neuroscience at Ohio State University and director of the study. She states that The hypothalamus is the most sexually dynamic area of the brain. Furthermore, it is very important for male-type reproductive and social behaviors, such as provoking maternal behavior in females”.

The importance of estrogen in sexual traits

The team observed the behavior of male rats, with inactive mast cells, when exposed to females that are ready to mate.  Compared to control male rats, they showed a lower degree of interest in mating. Conversely, female rats with active mast cells displayed sexual behavior generally typical of male rats.

Lenz explains that this is fascinating to watch, as ‘male’ females don’t have the ‘hardware’ to engage in male reproductive behavior. However, this couldn’t be seen from the way they acted. In fact, Lenz noted that “the rats seem to be strongly motivated to try to engage in male sexual behavior with other females”.

The researchers found that estrogen activates mast cells in the brain and that mast cells drive the animal’s sexual development. Indeed, estrogen plays an important role in the development of male traits.

Scientists know that hormones program gender differences during early development. However, they have limited information about changes at the cellular level that contribute to the way the brain and behavior form.

Immune cells in influencing sexual behavior

Researchers suggest that we need to learn more about behavioral development. In particular, learning how changes take place at the cellular level while the fetus is still in the womb.

Certain events experienced during pregnancy could be a possible factor. These events may influence the biological makeup of the fetus and behavioral trends. For example, allergic reactions or different types of injuries that trigger inflammation.

“These mast cells in the brain appear crucial for life-long brain development, even though there are relatively few of them, and this should really open our eyes to the potential role of different immune cells in the human brain” explains Lenz. She concludes, “There’s so much we don’t know, and we need to pay attention to all the cells in the brain and how they talk to each other”. 

Immune cells influence our sexual behavior



This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.