When I was four I went to live with my grandmother for a few years. She was a quiet woman, but kind and generous. Being a grandparent is all the best parts of being a parent without the hard bits. You get to give your grandkids chocolate, but don’t have to deal with the cavities.

Unusually, she followed a vegan diet. And her cuisine was truly some of the best you can imagine — some unholy mixture of vegan with traditional British cooking. No kale salad here — she’d serve up roast parsnips with braised tofu and pease pudding. I’m sure the style died with her. Or I suppose it might with me.

After two well-fed years living with her, I started to notice something strange. I was growing breasts.

At first I decided this was just the way things were. As a young boy living only with women, I figured I was becoming like them. But then my mother came to visit. I couldn’t understand what she and my grandmother were talking about, but I knew I wasn’t meant to, and I knew what it was about.

We went to the doctors next week. When they found out I was effectively on a vegan diet they decided that was the cause. They prescribed me a low dose of antiestrogens and instructed my grandmother to transition me back to an ordinary omnivorous diet.

The first evening she cooked me lasagne. She smiled as she gave it to me, but I didn’t finish it. Over the following weeks and months as my breasts shrank her smile became weaker and weaker and eventually disappeared. She wasn’t happy, but she knew it was the right thing to do.

When she died, some years later, I took up drinking soy milk again. In coffee or oatmeal to start with, but then I started drinking it straight. Once I drank three cartons in a single day. But by then I had testosterone, and in any case, it probably wasn’t soy in the first place. As I keep telling my brother, it’s not true, it can’t have that big an effect — just think of Japan. But he persists in buttering my toast with dairy, sometimes he even seems angry.

“You’re a man,” he says, “you need to protect it. Especially these days.”