This story appears in the January 2017 issue of National Geographic magazine.

Lots of people are talking about Avery Jackson, a nine-year-old girl from Kansas City who is the first transgender person to appear on the cover of National Geographic.

National Geographic is trying to brainwash young people into thinking this kind of degeneracy is normal. #GenderRevolution pic.twitter.com/BgurVzAEoU — Dirty Harry (@HarryCallahan_) December 15, 2016

Since we shared photos of the cover of our special issue on gender on Instagram, Facebook, and Twitter, tens of thousands of people have weighed in with opinions, from expressions of pride and gratitude to utter fury. More than a few have vowed to cancel their subscriptions.

These comments are a small part of the profound discussion going on right now about gender. Our January issue focuses mostly on young people and how gender roles play out around the world. For one of our stories, which we also turned into a series of videos, we went to eight countries and shot portraits of 80 nine-year-olds, who talked to us in brave and honest ways about how gender influenced their lives.

One of them was Avery. She has lived as an openly transgender girl since age five, and she captured the complexity of the conversation around gender. Today, we're not only talking about gender roles for boys and girls—we're talking about our evolving understanding of people on the gender spectrum.

The portraits of all the children are beautiful. We especially loved the portrait of Avery—strong and proud. We thought that, in a glance, she summed up the concept of "Gender Revolution."

Like her, all of us carry labels applied by others. The complimentary ones—“generous,” “funny,” “smart”—are worn with pride. The harsh ones can be lifelong burdens, indictments we try desperately to outrun.

The most enduring label, and arguably the most influential, is the first one most of us got: “It’s a boy!” or “It’s a girl!” Though Sigmund Freud used the word “anatomy” in his famous axiom, in essence he meant that gender is destiny.

View Images Nine-year-old Muslim girl Nasreen Sheikh in the impoverished, overcrowded slum where she lives in Mumbai, India. Nasreen wants to be a doctor when she grows up. She says that if she was a boy she would go and earn money so that she could “get stuff for her family.” Photograph by Robin Hammond

Today that and other beliefs about gender are shifting rapidly and radically. That’s why we’re exploring the subject this month, looking at it through the lens of science, social systems, and civilizations throughout history.

In a story from our issue, Robin Marantz Henig writes that we are surrounded by “evolving notions about what it means to be a woman or a man and the meanings of transgender, cisgender, gender nonconforming, genderqueer, agender, or any of the more than 50 terms Facebook offers users for their profiles. 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 baby’s sex, full stop: XX means it’s a girl; XY means it’s a boy. But on occasion, XX and XY don’t tell the whole story.”

In another story, looking for a future-facing perspective on gender, we talked to kids. The same piece that features Avery showcases young people from the Americas to the Middle East, from Africa to China. These keen and articulate observers bravely reflected our world back at us.

Nasreen Sheikh lives with her parents and two siblings in a Mumbai slum. She’d like to become a doctor, but already she believes that being female is holding her back. “If I were a boy,” she says, “I would have the chance to make money … and to wear good clothes.”

I expect Nasreen will learn that gender alone doesn’t preclude a good life (or, for that matter, ensure it). But let’s be clear: In many places girls are uniquely at risk. At risk of being pulled out of school or doused with acid if they dare to attend. At risk of genital mutilation, child marriage, sexual assault. Yes, youngsters worldwide, irrespective of gender, face challenges that have only grown in the digital age. We hope these stories about gender will spark thoughtful conversations about how far we have come on this topic—and how far we have left to go.

Thank you for reading National Geographic.