It’s unnatural, I tell you, unnatural!
The gender-sexual identity issue has been rumbling for a long time often pivoting around what is ‘natural’.
It was in the 1990s that Canadian linguist, Bruce Bagemihl PhD, fed up with being told that homosexuality was unnatural, collected and collated as many examples of scientifically documented cases of homosexual and bisexual behaviour in nature as he could find. His book, the first on animal homosexuality, contained so much evidence that it was thick as a doorstep! One chapter entitled, "A Wondrous Bestiary," profiled over 190 species in which scientific observers have noted homosexual or transgender behaviour. Since the first edition, that number has risen to 450 species of mammals, birds, reptiles, insects, and other animals worldwide. His book [Biological Exuberance: animal homosexuality and natural diversity] was so revelatory that it was used to take down sodomy laws in the United States. No-one can argue with the fact that in the natural world, male-male and female-female sexual relationships are a common addition to male-female ones.
Biologists studying animal behaviour are aware that there has never been a simple binary division even within species which officially have only two fixed sexes. Nature loves diversity. In humans, even at the genetic level, it is not the case that there are only two genotypes, one male, one female. You will have heard that females have XX chromosomes whereas males have XY chromosomes, but there are other combinations. XXX females and XXY males (who are usually infertile). Around one in 1,000 boys have an extra Y chromosome producing an XYY genotype. And when it comes to identifying genitalia, there are male, female, and what medics describe as ‘intersex’ genitalia birth. At no stage do we humans only have two forms.
Sex is also influenced by conditions in the womb. Human embryos by default are all female but become male through a 2-step process of defeminisation and then masculinisation during foetal development. Conditions in the womb influence both or either of these stages.
Zoologically we are described as sexually dimorphic (having two forms) yet as a species we show biological diversity which is only one influence of complex gender identity. Even here we have more than two options. Looking at human cultural variations, it is unusual to find only two gender identities. When European immigrants discovered the indigenous people of north America, they were shocked to find that all Native American societies acknowledged three to five gender roles: Female, male, Two Spirit female, Two Spirit male and transgendered. The European immigrants proceeded to outlaw this gender identity and force everyone into an artificially binary culture. [full article here]
“The UK government defines sex as the biological aspects of an individual as determined by their anatomy, which is produced by their chromosomes, hormones and their interactions; generally male or female assigned at birth. They define gender as a social construction relating to behaviours and attributes based on labels of masculinity and femininity; gender identity is a personal, internal perception of oneself and so the gender category someone identifies with may not match the sex they were assigned at birth.”
Getting back to biology, nature does transgender. Many sexually dimorphic species start off male but later become female—and/or the other way around. Sex is often determined by environmental factors such as temperature, food availability or social situation. The bluehead wrasse fish that lives in small social groups in coral reefs in the Caribbean is a case in point. Only the male has a blue head—signalling his social dominance over a harem of yellow-striped females, but if this male is removed from the group, the largest female in the group changes sex to become male. Her behaviour changes within minutes. Within ten days, her ovaries transform into sperm-producing testes. Within 21 days she appears completely male. Being transgender is natural, i.e., found in nature.
Adding to all this dynamic diversity, environmental pollution is messing with the situation. Many species are becoming feminized by artificial ‘female’ hormones (xenoestrogens) from the breakdown of plastics. The levels in freshwater are a particular problem for fish. Sexual disruption is rife and a source of great concern for the conservation of many species. In many cases fish are experiencing a complete reversal of sex. Many amphibian species will go extinct because of disruption to their sexual physiology from pollution.
Meanwhile, human males are experiencing a plummeting drop in fertility. Sixty years of xenoestrogens in the diet and drinking water have contributed to man boobs, poor sperm quality and falling sperm counts. Men are now half as fertile as they were only one generation ago.
When it comes to the biology of sex, what is ‘natural’ is both diverse and dynamic.
Life’s rich tapestry and all that.