Yesterday I spent the morning perched on a tiny plastic chair, observing my son Waylon’s yoga class. Although I have studied yoga for years, kindergarten yoga was most enlightening. For instance, I learned that the lotus position can also be called “criss-cross applesauce.” And kindergarten apparently presents an exception to the ancient injunction that yoga must be performed barefoot. (I suspect that convincing a group of five-year-olds to put their shoes back on would challenge the inner calm of even the most accomplished yogi.)

But the most fascinating lesson occurred when the class paired up for “buddy time.”

The girls ran to their girlfriends with wide eyes and huge smiles. They hugged and swayed and held hands while they waited for the teacher to call out the next pose.

And the boys?

Same exact story. From the looks of joy on their faces, buddy time might have been Christmas morning. I watched as Waylon and his friend Charlie wrapped their arms around each other’s waists. Between poses, Charlie rested his head on Waylon’s shoulder.

I checked the other pairs of boys and found that they, too, were beaming and clinging to one another. Their happiness was infectious, but it also made my heart hurt. I took a deep breath and tried to stay in the moment, but I found myself already anticipating a future when this easy intimacy between boys would disappear.

Waylon is my first child, so I can’t say exactly when it might happen–second grade? fourth? middle school?–but I fear that, far too soon, the majority of these boys will have internalized the implicit and explicit rules of our culture’s version of masculinity. No more lounging with their head on their buddy’s shoulder, no more looking deeply and directly into his eyes.

Watching their little bodies lean against each other in supported bridge pose, I grieved for all that they might lose: the sense of trust and openness, the comfort of a friend’s touch. Girls have their own real and harrowing challenges in our culture, but I don’t think they are expected to eschew intimacy with same-sex friends as a rite of passage.

As adults, we sometimes defend against the awfulness of this loss by telling ourselves that these gender differences are inevitable, natural, even biological. But I defy any observer of kindergarten yoga to tell me that boys do not have the capacity to develop close, nurturing friendships with other boys. If we are honest with ourselves, we have to acknowledge that it is cultural forces–namely sexism and heterosexism–that threaten to impoverish the emotional lives of our sons.

At the end of class, the instructor asked the kids if they remembered the intention that they had set at the beginning. “To be happy!” they called in chaotic harmony.

As I walked out the door, I wanted to collar every parent in that class and plead with them:

Don’t teach your sons that boys can only touch when they are fighting or playing sports.

Don’t teach them to hold themselves stiffly and keep their eyes to themselves.

Don’t teach them by teasing and example.

Don’t do it for their future friends and lovers.

Don’t do it because you want them to be happy and because it diminishes the sources of comfort and support that are available to them in this hard and crazy world.