You'd have to be more specific about what progressives are denying in science, climate change, biology, etc.
From the National Geographic article:
How Science Is Helping Us Understand Gender
....At the same time, scientists are uncovering new complexities in the biological understanding of sex.
Many of us learned in high school biology that sex chromosomes determine a babyâs sex, full stop: XX means itâs a girl; XY means itâs a boy. But on occasion, XX and XY donât tell the whole story.
Today we know that the various elements of what we consider âmaleâ and âfemaleâ donât always line up neatly, with all the XXsâcomplete with ovaries, vagina, estrogen, female gender identity, and feminine behaviorâon one side and all the XYsâtestes, penis, testosterone, male gender identity, and masculine behaviorâon the other. Itâs possible to be XX and mostly male in terms of anatomy, physiology, and psychology, just as itâs possible to be XY and mostly female.
Each embryo starts out with a pair of primitive organs, the proto-gonads, that develop into male or female gonads at about six to eight weeks. Sex differentiation is usually set in motion by a gene on the Y chromosome, the SRY gene, that makes the proto-gonads turn into testes. The testes then secrete testosterone and other male hormones (collectively called androgens), and the fetus develops a prostate, scrotum, and penis. Without the SRY gene, the proto-gonads become ovaries that secrete estrogen, and the fetus develops female anatomy (uterus, vagina, and clitoris).
But the SRY geneâs function isnât always straightforward. The gene might be missing or dysfunctional, leading to an XY embryo that fails to develop male anatomy and is identified at birth as a girl. Or it might show up on the X chromosome, leading to an XX embryo that does develop male anatomy and is identified at birth as a boy.
Genetic variations can occur that are unrelated to the SRY gene, such as complete androgen insensitivity syndrome (CAIS), in which an XY embryoâs cells respond minimally, if at all, to the signals of male hormones. Even though the proto-gonads become testes and the fetus produces androgens, male genitals donât develop. The baby looks female, with a clitoris and vagina, and in most cases will grow up feeling herself to be a girl.
Which is this baby, then? Is she the girl she believes herself to be? Or, because of her XY chromosomesânot to mention the testes in her abdomenâis she âreallyâ male?
Georgiann Davis, 35, was born with CAIS but didnât know about it until she stumbled upon that information in her medical records when she was nearly 20. No one had ever mentioned her XY status, even when doctors identified it when she was 13 and sent her for surgery at 17 to remove her undescended testes. Rather than reveal what the operation really was for, her parents agreed that the doctors would invent imaginary ovaries that were precancerous and had to be removed.
In other words, they chose to tell their daughter a lie about being at risk for cancer rather than the truth about being intersexâwith reproductive anatomy and genetics that didnât fit the strict definitions of female and male.
âWas having an intersex trait that horrible?â wrote Davis, now a sociologist at the University of Nevada, Las Vegas, in Contesting Intersex: The Dubious Diagnosis. âI remember thinking I must be a real freak if even my parents hadnât been able to tell me the truth.â
Another intersex trait occurs in an isolated region of the Dominican Republic; it is sometimes referred to disparagingly as guevedoceââpenis at 12.â It was first formally studied in the 1970s by Julianne Imperato-McGinley, an endocrinologist from the Weill Cornell Medical College in New York, who had heard about a cohort of these children in the village of Las Salinas. Imperato-McGinley knew that ordinarily, at around eight weeks gestational age, an enzyme in male embryos converts testosterone into the potent hormone DHT. When DHT is present, the embryonic structure called a tubercle grows into a penis; when itâs absent, the tubercle becomes a clitoris. Embryos with this condition, Imperato-McGinley revealed, lack the enzyme that converts testosterone to DHT, so they are born with genitals that appear female. They are raised as girls. Some think of themselves as typical girls; others sense that something is different, though theyâre not sure what.
But the second phase of masculinization, which happens at puberty, requires no DHT, only a high level of testosterone, which these children produce at normal levels. They have a surge of it at about age 12, just as most boys do, and experience the changes that will turn them into men (although theyâre generally infertile): Their voices deepen, muscles develop, facial and body hair appear. And in their case, what had at first seemed to be a clitoris grows into a penis.
When Imperato-McGinley first went to the Dominican Republic, she told me, newly sprouted males were suspect and had to prove themselves more emphatically than other boys did, with impromptu rituals involving blades, before they were accepted as real men. Today these children are generally identified at birth, since parents have learned to look more carefully at newbornsâ genitals. But they are often raised as girls anyway.
Gender is an amalgamation of several elements: chromosomes (those Xâs and Yâs), anatomy (internal sex organs and external genitals), hormones (relative levels of testosterone and estrogen), psychology (self-defined gender identity), and culture (socially defined gender behaviors). And sometimes people who are born with the chromosomes and genitals of one sex realize that they are transgender, meaning they have an internal gender identity that aligns with the opposite sexâor even, occasionally, with neither gender or with no gender at all....
