There is little doubt that in the last decade the topic of gender identity has migrated from the edge of the conversation to the centre of its own political and social maelstrom.
And while it might seem politically provocative and medically complex, at its heart sits something far more fragile than either of those things: real lives, for whom the search for answers is both necessary and meaningful.
On the media radar there are prominent figures such as Caitlyn Jenner and Laverne Cox whose narratives seem to suck up much of the oxygen in the mainstream. And a raft of pop culture which taps the subject, notably television programs such as Transparent and Orange Is The New Black.
"A day doesn't go by, and this is really one of the reasons I wanted to tackled this topic, where you don't see something about gender going on," American journalist and former Today show host Katie Couric tells The Guide.
That is, she says, a combination of both the increased profile of transgender narratives and also a greater willingness, in society, to open up the conversation. And in part it is thanks to Olympian-turned-reality star Caitlyn Jenner, whose television program effectively took the issue properly into America's living rooms.
"Caitlyn Jenner's high visibility introduced this notion to members of the public who are just very unfamiliar with this and [for whom] it was out of their range of experience," Couric says.
But like most big issues, the first signs of it in Couric's world came at home, in conversation with her college-age daughter, who related an experience in which her class was invited to introduce themselves with their name and pronoun.
"It's not even preferred pronoun, it's your pronoun, and I said, gee, that's fascinating," Couric recalls. "One of her very close friends at college is transgender, and her attitude was so much more open-minded than people of my generation or younger."
That sat in stark contrast to Couric's own college experiences. "There were very few gay people when I went to college, [other than] my gay friend in the next dorm, and you know, it was so scandalous and shocking," she says. "Young people are very different in terms of their attitudes, and we need to try to understand it too."
Gender Revolution: A Journey with Katie Couric tackles a range of issues, both personal and scientific, and looks into questions ranging from the very simple – why do we feel we're a particular gender? – to more complex topics such as the alchemy of hormones, chromosomes, DNA and cultural and environmental influence.
Meeting with one of the program's key talking heads, Dr Joshua Safer, was, explains Couric, "critically important for me to begin to understand what science is starting to really look into, and still doesn't fully understand."
In truth, Couric explains, the numbers have not changed much in terms of individual experiences across the transgender spectrum. "But the visibility and our willingness to talk about it has," she says.
"I think we're at a really critical point in the conversation," she says. "If we don't have the context to understand [the headlines] or to digest these developments then I think it can be almost dizzying."
The shifting ground in American politics – an incoming centre-conservative president, powered by a ultra-conservative congress and senate – makes navigation of gender issues and the conversation around it even more pressing, says Couric.
"It becomes more important because I think there's many misconceptions out there about the nature of gender, [and] about so many attendant issues to this subject," she says.
"I've always lived with the philosophy: the more information people have the more knowledgeable they become and the more knowledgeable they become the more able they are to understand. That was really my goal."
And like the cultural battlegrounds of feminism and sexuality before it, gender identity does not always find unwavering support from within its own communities: the notion that some women reject feminism and some elements of the gay community reject the mainstream drift of their cultures.
"Any revolution – you know maybe it would have been more appropriate to call it an evolution – any sort of big shift in cultural norms kind of happens in fits and starts with some disagreement within that particular group," Couric says.
"I think that's healthy in a way, because I think we all need to have conversations, because this has wide-ranging implications, and really does change what whomping the status quo of how we categorise ourselves and each other in society at large," she adds.
"There are gonna be steps forward and steps backwards," Couric says. "Hopefully more information, and more understanding, can at least allow us to have a more productive conversation. That's really my goal in doing this.
WHAT Gender Revolution
WHEN Nat Geo People, Wednesday, 8.30pm