What peer-reviewed science says about gender fluidity

There is a growing amount of research diving into sex (biological anatomy) and gender (social construction).

We've all heard the vehement declarations about what is or is not "natural" for humans. Those who land on the "same-sex marriage is unnatural"/ "dominant women are unnatural"/ "a man is meant to be an alpha" side tend to adopt this argument most aggressively.

It's not just men fearing the loss of their power who make such claims. A significant percentage of women also passionately declare what is and is not "biologically natural".

However, if you dig into it and remove emotional and personal motivations, you'll find that these claims aren't supported.

I asked chatGPT:

Here are a few morsels of science ->

1. Effects of gendered behavior on testosterone in women and men

Findings indicate that social conditioning and the opportunity to wield power influence testosterone. This is opposed to traditional beliefs that testosterone is primarily tied to biological sex. This means that it's unlikely that "men are biologically wired to be dominant" but rather that "men are permitted to wield more power and thus accumulate more testosterone which drives dominance behavior". This study has 108 participants.

...Our findings show that discrete events of gender-related socialization may account for some portion of the observed “sex” difference in adult testosterone levels. This adds to growing evidence that gender and sex are more permeable categories than is typically accounted for in bioscientific research and opens up new questions about physiological pathways that link gender socialization to human biology.

2. Bitch - on the female of the species

Written by a Zoologist, this book digs into the heavily biased foundation of sex-based animal research.

For decades Victorian-influenced scientists have been throwing out any research that was contradictory to the story that "the female is a passive participant, with its purpose only being to incubate offspring". Females are often categorized as being passive while males are active. Look at peacocks and other males of other species. The male almost always has more bling. The male must therefore be far more important for driving evolution.

In actuality, in significantly large quantities, the female of various species are the drivers of evolution. They are far more promiscuous, and ultimately it's their choice which genes get passed on or not. In many species (hyenas, killer whales, lions, bonobos, lemurs, elephants, and more) the female is the key pack leader.

The binary of"sex" is actually a very difficult binary to establish. You could say "the male has testes" and "the female has ovaries," but that would ignore all of the other factors that go towards determining "sex". Several animals change their sex from puberty -> adulthood, some can even switch sexes as full grown adults. Same-sex intercourse between animals is also common.

The point of this book is not to say that the female is meant to be leader, it's merely to scientifically disprove the hypothesis that "males are meant to lead". Darwin and his peers originally championed this belief, but now we know it was heavily biased and therefore not accurate.

TLDR

1. There is nothing inherent to "male-ness" to make them active and nothing inherent to "female-ness" to make them passive

2. The biological pathways of forming an animal's sex are extremely complicated and intertwined. Any binary understanding of gender and sex simply isn't backed by science.

3. The gender-binary cycle: the perpetual relations between a biological-essentialist view of gender, gender ideology, and gender-labelling and sorting

This study looked into biological differences between men and women.

Research from neuroendocrinology, neuroscience and psychology often reveals group-level differences between women and men, but does not support the biological-essentialist beliefs that these differences are immutable, nor the assumption that human brains, hormones and 'natures' belong to two distinct kinds.

...endocrinology research reveals that humans do not possess one of two sets ('female' or 'male') of sex-related hormones. Rather, hormones that are considered 'female' (oestrogen and progesterone) and those considered 'male' (testosterone) are present in both men and women as they are produced by both ovaries and testes as well as by additional tissues that are present in all bodies...men and women do not differ on average in their levels of oestradiol and progesterone.... sexual thoughts increase testosterone levels in women and nurturing parenting behaviors decrease testosterone in men. Thus, gender differences in levels of sex-related hormones do not conform to a fixed and binary conceptualization.

Human brains also cannot be meaningfully sorted into 'female' and 'male'. Although there are group-level gender differences in many brain measures (e.g. size of specific brain regions, strength of connections between regions), there is a great deal of overlap between the distributions of women and men for each of these measures...a study of over 2100 human brains...found that the brain architectures typical of women are also typical of men, and vice versa.

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My favorite place to find aggregated research papers is elicit.org.

Here's a direct link to explore more on this topic, you'll need to make a free account.