I let my boy/girl twins cross-dress on a regular basis. Not only do they share a closet, they are in the throes of the toddler independence movement, which means what they wear from said closet is a topic of endless negotiation. When you are two and a half, clothes are the way, par excellence, to assert your individuality and control your environment in one fell swoop. Outfits change in our house with the weather or with the mood or with the infusion of unwanted fluids. And when the boy picks the purple pajamas and the girl asks for her brother’s “trousers,” that’s what they each get.

Early gender identity is a fascinating—and complicated—mixture of the genetic and the cultural. There is no denying that some differences between males and females are hard-wired. Most of us who have raised each kind of kid will attest to innate traits that are stereotypically sex-specific. But then there are the soft-wired tendencies, the ones that are generated not by DNA but by society. These are the ones we commonly reinforce in our homes—through clothes, toys and expectations—whether intentionally or not. According to Lise Eliot, the author of Pink Brain, Blue Brain, parental attitudes toward gender are far more determinative of behavior than we give credit for.

I like to consider myself progressive on the soft-wiring front. In a family comprised of three sons and one daughter, our toy selection, for example, is pretty balanced: cars mixed in with dolls mixed in with musical instruments mixed in with tea sets. There are no rules about who can play with what. The boys are encouraged to feed the babies, the girl to wield a lightsaber. The colors that decorate it all are primary, mainly, though the palette has come to include some pinks and pastels in recent years.

And yet, conservatism shows its truest colors in those arenas of change that aren’t even on the radar. My older sons only wore clothes from the boy side of the store: I never thought twice about it. From the time they were tiny, their wardrobes have been Y-chromosome-themed, in the most conventional of ways. The onesies were smattered with trains and footballs, the sleep-suits with various shades of blue. And because they were both male, we didn’t have any “girl” clothes or accessories on offer, had the desire to “experiment” been there.

With my twins, however, the practical (but very compelling) stumbling block of availability disappears. Consider the pair of magenta, alligator-print wellington boots standing in the hall. They were a present from a doting grandparent for the lone granddaughter of the group, but they have caught the eye of grandson number three instead. What’s more, they are exactly the right size. He wants to wear them to the park. What do you do?

At two years old, you let him. Or at least I do. His choices at this age are not reflective of a gender “non-conforming” attitude, nor are they likely to be the subject of merciless teasing. If I were to redirect him to footwear that is more masculine or “appropriate,” I wouldn’t be doing it to protect him. I would be doing it to teach him something. But what is the lesson? It’s hard, I admit, not to feel a cognitive dissonance at the sight of a little boy in pink shoes—especially when that little boy, like mine, has the baby version of a rugby player’s body. That’s my issue, though, not his.

I talk the talk about gender fluidity—and in this instance I let my son walk the walk—but I wonder how long it will last. In the coming months, both of these toddlers will begin to understand, increasingly, what it means that one of them is male and one of them is female. They are already keenly observant of the differences between their legs. Gender is an unmistakable, and important, part of the process of self-discovery. It is a process that reaches a fever pitch at three to four years old, when kids are notoriously swept up in the pre-school wake of “this is for girls” and “that is for boys.”

There is much to be welcomed about the way children naturally make sense of the world by categorizing themselves. There is also much that is artificial about it. Twins are a constant source of illumination in this respect, a reminder of the delicate interplay between the learned and the inherent. Mine have certainly shown me, even at this young age, how malleable conceptions of gender-specific behavior are. The initial interest might be typical or predictable, but where it goes from there is anything but.

My son, for instance, is captivated by the comings and goings of the garbage truck. My daughter has taken to joining him at the window for the daily look-out sessions and you can find them there discussing every manner of vehicle that passes by (Digger! Van! Bus!). My daughter, as soon as she could walk, would push her favorite monkey (“Bobo”) around the garden in a toy stroller, lovingly tending to his every need. My son now pushes his baby tiger (“Cocoa”) right next to her, breaking only to shower him with kisses or change his diaper.

The influence my boy/girl twins have over one another is profound and, in the absence of a parent discouraging the unconventional, they dip in and out of each other’s schemas of play routinely. The same way they dip in and out of each other’s wardrobes. Clothes might seem like a superficial manifestation of a child’s sex, but they are symbolic of a greater divide of skills and opportunity. My hope is that by letting my twins wear each other’s pajamas now, they will feel that bit less restricted by traditional gender roles in the future.

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