My son is working out.

My son is blessed with a beautiful face. He has my two best features: big, brown eyes and a nice smile. Thank God he does not have my nose; this, and those uniquely bushy eyebrows, are courtesy of his father. I believe he got the best we both had to offer.

At 12, he is well aware of how others see him, how they have seen him all his life. And he is tired of it. When a woman in line at the grocery store smiles at Robby and says to me, “You’ve got a handsome boy,” his face twists. He knows he should smile. He tries. Yet those remarkable eyes cut up to me with a look that says he’s both embarrassed and annoyed. Having grown up ugly, I am not overly sympathetic.

He is also scrawny. Perhaps slight or skinny are better terms. My brother-in-law puts it this way: “That boy’s a poster child for Ethiopia.” But I think that’s a tad extreme.

I say this factually, with love and empathy. I, too, was scrawny. In 8th grade, I stood at 85 pounds.

My sixth grader weighs around 80 pounds. In swim trunks, his shoulder blades jut out from his back like bird wings. I can count his every rib. His appetite is as small as he is. His metabolism is mine on crack. Fast. Very fast.

Other boys his age are filling out as they grow. Robby’s just growing.

Friday night, I found him doing sit-ups in his room. Twenty-five each night, he said. Knees bent, hands clasped behind his head, boy-sized exhalations escaped him as he pulled his chest up and over his torso. His tennis shoes slid out a few inches with each sit-up. On the way down, he pulled them back into position.

I felt a curious combination of pride and pain. Pride in the efforts he’d taken on by himself. Pain in knowing he was now aware of his body, and found it lacking.

Saturday night, he suggested we turn on Exercise TV. He wanted to focus on abs and shoulders, so we chose a 20-minute program with a too perky blonde instructor. Lacking hand weights, I gave him two thick pillar candles to grasp. Not much weight, but the size was about right.

Five minutes into the routine, I felt my shoulders burning. Robby plowed through without complaint.

“We should do that again!” he said.

“Sure,” I agreed. “But you need to let your muscles rest a while. A good, long while. Maybe we’ll do it in two weeks when you’re back next!”

He frowned but nodded. He has little choice. Cable service isn’t available at his dad’s ranch.

This change in my son stirs another emotion: Yearning. For the fat, laughing baby that was, the white-blond toddler long since vanished, the wide-eyed elementary school student fast fading into memory.

My child is 12, and his mind is opening to new ideas. Life isn’t necessarily all about play and homework. It sometimes means enduring physical discomfort and pain with a longer-term goal in mind: A better self-image, more respect from male peers, and though he won’t yet admit it, the admiration of girls.

In other words, he’s showing all the signs of becoming a teenager.

I can’t stop it, nor truly do I want to. I can support and encourage him. And how cool it is that we have found yet another thing we can do together: Making fun of bouncy instructors and taxing our muscles to Exercise TV.

Hand weights are now on my shopping list. I’ll start him with two pounders. Me, I'll take those candles. They’ll do just fine.