Was in training a few years ago and the proctor, male, had boobs just like a woman. No trans stuff. Not gay or anything(as far as we know), not fat or obese. He was simply a 'man' who grew boobs. That was an awkward class. Especially when he would squat or bend over for something. Those things were flopping around. I had to look away. It was disturbing to me.
But yes, there are men who grow boobs just for no reason. Sometimes it happens.