“Sex is supposed to be simple — at least at the molecular level. The biological explanations that appear in textbooks amount to X + X = and X + Y = . Venus or Mars, pink or blue. As science looks more closely, however, it becomes increasingly clear that a pair of chromosomes do not always suffice to distinguish girl/boy — either from the standpoint of sex (biological traits) or of gender (social identity).
In the cultural realm, this shift in perspective has already received a wide embrace. “Nonbinary” definitions of gender — transfeminine, genderqueer, hijra — have entered the vernacular. Less visible perhaps are the changes taking place in the biological sciences. The emerging picture that denotes “girlness” or “boyness” reveals the involvement of complex gene networks — and the entire process appears to extend far beyond a specific moment six weeks after gestation when the gonads begin to form.
To varying extents, many of us are biological hybrids on a male-female continuum. Researchers have found XY cells in a 94-year-old woman, and surgeons discovered a womb in a 70-year-old man, a father of four. New evidence suggests that the brain consists of a “mosaic” of cell types, some more yin, others further along the yang scale.”
https://www.scientificamerican.com/article/the-new-science-of-sex-and-gender/
“The [Trump regime’s] proposal — on which HHS officials have refused to comment — is a terrible idea that should be killed off. It has no foundation in science and would undo decades of progress on understanding sex — a classification based on internal and external bodily characteristics — and gender, a social construct related to biological differences but also rooted in culture, societal norms and individual behaviour. Worse, it would undermine efforts to reduce discrimination against transgender people and those who do not fall into the binary categories of male or female.
Furthermore, biology is not as straightforward as the proposal suggests. By some estimates, as many as one in 100 people have differences or disorders of sex development, such as hormonal conditions, genetic changes or anatomical ambiguities, some of which mean that their genitalia cannot clearly be classified as male or female. For most of the twentieth century, doctors would often surgically alter an infant’s ambiguous genitals to match whichever sex was easier, and expect the child to adapt. Frequently, they were wrong. A 2004 study tracked 14 genetically male children given female genitalia; 8 ended up identifying as male, and the surgical intervention caused them great distress (W. G. Reiner and J. P. Gearhart N. Engl. J. Med. 350, 333–341; 2004).
Even more scientifically complex is a mismatch between gender and the sex on a person’s birth certificate. Some evidence suggests that transgender identity has genetic or hormonal roots, but its exact biological correlates are unclear. Whatever the cause, organizations such as the American Academy of Pediatrics advise physicians to treat people according to their preferred gender, regardless of appearance or genetics.
The research and medical community now sees sex as more complex than male and female, and gender as a spectrum that includes transgender people and those who identify as neither male nor female. The US administration’s proposal would ignore that expert consensus”.
https://www.nature.com/articles/d41586-018-07238-8
“”The idea of female and male brains is outdated and never reflected the science,” van Anders, the Canada 150 research chair in social neuroendocrinology, sexuality and gender/sex at Queen’s University, told Quirks & Quarks host Bob McDonald.
“It’s not a one size fits all when it comes to your sex and gender.”
…
“According to van Anders, evidence of trans and non-binary people have been found dating back thousands of years. Pottery found in ancient Egypt dating back to the year 2,000 BC shows depictions of three genders.
“Trans is nothing new,” she said.
“Transgender people, living in genders that branch from what they were assigned at birth, have been around a long, long time. Various indigenous nations have diverse gender experiences, including what is now called two-spiritedness. Cultures in Eastern Europe, East Asia, all over the world have multiple genders or third genders.””
