(CNN) For his birthday this year, my 5-year-old son asked for a My Little Pony sweatshirt. He didn't know that it was categorized as girls' clothing, only that, like his beloved Rainbow Dash, it was polychromatic, glittery, winged and perfect.

He has spent his early years in Oakland, California, largely surrounded by adults who avoid use of the nouns "boys" and "girls" unless necessary. His world is blissfully, ignorantly gender-neutral.

In the fall, he'll be heading to elementary school, and I was thinking it might be time to explain to him that as natural as his love for this sweatshirt is, there are a lot of people who find a boy in a girl's sweatshirt unnatural and won't hesitate to let him know.

The hardest part of this conversation will be what, inevitably, will follow. He, a scrupulous monitor of fairness in matters large and small, will ask whether there are also things people think girls shouldn't wear. I, remorsefully, will have to tell him "no."

Gender progress: a one-way street

Though feminism has made great progress in stripping childhood of gender norms, the efforts have been awfully lopsided.

Meanwhile, there's still not a single traditionally feminine thing a boy can do that wouldn't raise eyebrows. A boy who likes wearing jewelry or makeup, twirling in a tutu or caring for baby dolls is at best the subject of conversations conducted sotto voce. At worst: a bully's target.

The tomboy phenomenon is more than 400 years old and has gone from outsider to aspirational to anachronistic over the course of the 20th century; the tomgirl remains a nonstarter. Describe a boy with a phrase that includes the word "girl" in it, and you're likely to make his parents' spines quiver, including those of many of the feminist dads I know.

Parents are increasingly giving their daughters boy names like James and Finn; few among us would dare give our sons a girl name, because pity the boy named Jenn or Sofia. Girls fought and won the right to join the Boy Scouts; I'm not going to hold my breath waiting for boys to gain entry to the Girl Scouts.

All this might make you conclude that girls have it better. And in some ways, they do.

"Women have changed what it means to be a woman and embrace a much larger human canvas. Men are still painting on half the canvas," said Michael Kimmel, a professor of sociology and gender studies and author of " Guyland: The Perilous World Where Boys Become Men ."

"Now, it's perfectly permissible for girls to (enter) boyland, but heaven help the boy who wants to move to the other side."

But a closer look at this gender revolution among children reveals to what degree this whole enterprise has been tipped in favor of the masculine.

Barbie has been a member of the armed forces, a presidential candidate and an engineer; boys' dolls continue be, nearly exclusively, action figures conscripted to battle. Disney movies have featured a number of macho or strong and brave female characters, including "Pocahontas" (1995), "Mulan" (1998) and "Moana" (2016); meanwhile, the male characters continue to alternate between brute and naïf.

Girls get to flip through books like " Strong is the New Pretty ," but no publication is telling boys that typically feminine traits like caring for others or, yes, taking an interest in beauty (which is often tsked tsked in boys) is the new strong.

Girls have been told that they can do anything, be anything, and they largely can, without judgment. However -- and here's the catch -- that's true only if they are physically strong and career-oriented and eschew most of the traditional trappings of femininity. In short, they will gain respect if they act like boys.

"It's about mobility. Girls who act like boys are moving up the social ladder. Boys who are acting like anything but masculine are moving down and risk losing their status," Kimmel said.

Expanding the definition of 'boyhood'

That there is no cultural infrastructure to support slightly feminine boys like mine only underscores this point. Where are the books, movies, toys and video games working to gently expand the notion of boyhood, quietly and uncontroversially permitting them to take pride in their love of pink glittery hearts, baby dolls or whatever else their budding hearts desire?

A bedazzled ninja turtle or a feature film about a peasant boy who falls hopelessly in love with princess would help all children feel more emboldened by their girlier proclivities.

Richard Gottlieb, founder and CEO of Global Toy Experts and publisher of Global Toy News, said the toy industry has experienced far more pressure to expand the definition of girls' toys than it has to expand the definition of boys' toys.

"Almost all the social demand has been on the girls' side," Gottlieb said.

But he's not without hope. In 2017, the toy industry did away with the categories of "boy toy" and "girl toy" in its Toy of the Year Awards, and there's been a small uptick in dolls marketed to boys.

"I think you are going to see more ('girl' toys marketed to boys or as gender-neutral), but it is going to come later," Gottlieb said. "Remember, you still have 20th-century leadership marketing to 21st-century young adults. As these young adults move their way up through the ladder, you are going to see more and more gender neutrality."

My search for boys toys and media geared at "feminine" boys has yielded very little. I found a handful books written for gender-nonconforming boys that do some of this work, but they aren't the right fit. My son freely and easily identifies as a boy. He doesn't need our help in his rejection of the label of "boy"; he needs the meaning of that label to expand.

I get it. Permitting, let alone encouraging, boys to be more girly is scary. We want our boys to keep being like boys because masculinity is still where the power lies. And we want our girls to be more like boys for the same reason. But while that method of seeking gender equality has worked, there are limits to how far it can get us.

In her recent book " Women and Power: A Manifesto ," Mary Beard encourages readers to scrutinize our notions of power, particularly those inhospitable to behaviors and experiences traditionally associated with women. "If women are not perceived to be fully within the structures of power, surely it is power that we need to redefine rather than women?" she writes.

Widening the perimeters of boyhood would be a great place to begin this work of redefining power. It should, as others have suggested , help inoculate boys against the stoicism and aggression some of them experience in their teenage years.

Raewyn Connell, author of " Masculinities ," said many teenage boys still feel as though they must avoid any signs of weakness or femininity. This, in turn, feeds homophobia, because gay men are associated with the parts of themselves that they feel they must suppress.

"With teenage boys, the search for respect and recognition often results in exaggerated displays of dominating masculinity: the football hero, the first guy in the peer group who smokes, the playground bully, etc.," Connell said. This is often accompanied by "a stark rejection of 'girl things.' "

Broadening boyhood will also help give legitimacy to women's work and interests, bringing things like beautification, compromise and caring for others into the official range of human endeavors that truly matter.

Recently, I came across a Twitter thread explaining the backstory to the Etsy-favorite quote "Well-behaved women seldom make history." We've long interpreted it as a call to arms for women to put down their babies, oven mitts or lipstick and start making some noise -- like a man. But it turns out the line was written with another agenda in mind.

Historian Laurel Thatcher Ulrich included the sentence in a paper about women in colonial America, whose domestic existences had largely rendered them uninteresting to historians and therefore absent from history books. Ulrich wasn't telling women to act more like men; she was telling us to pay more attention, and imbue more importance, to a traditionally feminine existence. In other words, "well-behaved women seldom make history" ... because nobody thinks that what they are doing is worthwhile.

Join the conversation on CNN Parenting's Facebook page See the latest news and share your comments with CNN Parenting on Facebook.

I bought my son the Rainbow Dash sweatshirt, and he wears it on a regular basis, on top of his equally adored superhero t-shirts and paired with his knee-worn pants. We never had a talk, but his breezy confidence in wearing this flamboyant hoodie suggests that he doesn't need one, at least not yet. For him, there is no inconsistency between boy and glittery rainbow, and this palpable certainty serves as an invitation for others to feel the same.

He also doesn't need my protection. He needs my support, a beaming mom waving from the sidelines as he seeks to make his version of well-behaved history, by way of glittery wings or whatever else he chooses to keep him afloat.