Bullied and miserable, Ewan Morrison developed a severe stutter at the age of 10. His father also stuttered for years following a secret childhood trauma. So was there a link - and was the family history to blame?

I pride myself on my strong voice. I am loud and outspoken, and take pleasure in provoking people into speaking their minds. My friends often catch me at it and ask me, quietly, to calm down. What I have never told them is that when I was 10 I could barely say a single word for fear of stuttering. I recall that horrific gasping for breath, my tongue tying itself in knots and my eyes searching the ceiling in shame as the jaw spasms started - all from trying to answer one simple question at the start of the school year: 'And your name is ... ?'

Ewan was hard to say, words starting with ah or oh sounds were easier, words starting with consonants - impossible. There were techniques, of breathing and mental focus, that my father taught me, that sometimes helped or sometimes made it worse. "Always take a breath before you start, don't hold it in. Think of the first sound, not the rest, and breathe it out."

In the classroom, the humiliation was not mine alone. There was a communal intake of breath before I tried to speak. The whole room suffered with me. Some covered their eyes, others started giggling, a kid in the back row often muttered "spastic". The teacher made it even worse, her eyes filled with pity, as I fought for breath. I knew that she had been schooled in the philosophy that says you should never interrupt a stutterer - let him finish for himself. As my father, David, had taught me. A sufferer himself, he had been unable to speak from the age of 10 until 25.

He is 66 now, and still stumbles on words. I occasionally see his eyes flicker and avoid my gaze, as his fingers twitch and he reaches for breath. I no longer stutter and find it traumatic to recall that time. I have a son now, aged 10, and am grateful that the condition has not passed again from father to son, as it can, virulently, through a family. My father, having endured some of the most horrific experiments in the evolution of the science of speech impediments, confirms again and again that it is a psychological condition. It starts from an initial trauma, then becomes its own trauma. The one thing that my father has taught me, that I believe, is that stuttering always starts from "feared words".

He has often told me the story of the first time he stuttered. It was 1945 and a minister of the Church of Scotland, my grandfather Jacob Morrison, stood before his congregation in a church in Glasgow, and talked passionately against the war, of man's inhumanity to man, and concluded that no real God could condone such suffering. Before the congregation he had spent years building, he renounced his faith. In the front row was his wife, Jessica, whose father had been a key figure in the Church of Scotland. And beside her, her son; my father.

He always cries when he recounts the story. When my grandfather came home that night the door was barred to him. Divorce was unheard of in that time among the church elite, but Jessica told her son that he was not, ever again, to mention his father's name. And so began my father's 15-year struggle to speak.

In the years that followed, his mother, embarrassed by his condition, took him to doctors and psychologists, quacks and faith healers. Even to this day, the science of stuttering is caught up in the false idea that it is a biological condition, with DNA experiments and antipsychotic drugs. Only one person, a speech therapist at my father's school, sensed the truth, and quietly asked how things were at home. My grandmother, on hearing about it, forbade her son from speaking to the therapist again.

I often think of my grandfather, alone at the lectern as his congregation abandoned him and his wife silently led her son away.

My father moved as far as he could from his past. He was liberated by the 60s and became a hippy and, like his father, an atheist. He went north, to the furthest extremity of Scotland, and worked hard to create a new life for his family. I can only imagine his horror then, on discovering that his 10-year-old son had developed a stutter.

The irony was that it was his desire to escape the past that brought it back. It was the remote town we had gone to. It was my middle-class hippy voice. The kids at school called me "snob", "Englisher", "south mouther". They held me down and made me eat dirt. They cornered me in the bike shed and hit me, making me repeat words in their local dialect so that they could laugh at my voice.

So began the twitching, nodding, blinking, the tensing of muscles or pinching of skin. The fear of stuttering became the thing that made me stutter more. I now know that stuttering is very much like a panic attack.

The one person who could have helped me was the one who made it worse. I vividly recall the night, aged 12 and about to enter high school with a chronic stutter, when my father broke down and cried, told me about his father, and swore that history would not repeat itself: he would save me from it. And in that moment, he implanted in me an even greater fear of words.

My father is still trapped in his father's story. He only found out later that his father had secretly followed his teenage years. Whenever he'd played rugby, Jacob had been there, silent at the sidelines. The last time my father saw his father, Jacob was on his deathbed, dying of cancer - the only time his mother had let them meet after eight years apart. Jacob's last words were about rugby; he told his son to fear no one, to get into the thick of it, scrum down, use your anger.

My father's cure was multilayered: an increase in social responsibility and self-esteem, as well as singing lessons. He never stuttered when he sang and so he developed the idea that he could "sing his words". He now has a loud booming voice and always begins his sentences as if starting an aria.

For me, the cure was an unexpected one. My parents chose to play my condition down, to let time heal. I was 10 when it started and 13 when it stopped. The crucial turn-around years between primary school and high school, between childhood and adolescence. In those years I was livid with rage and hatred. I knew the answers to all the questions the teachers asked, but they always passed me over when asking the class. Friends were few and played with me, I knew, only because of the things my parents had bought me to compensate, the fancy toys, the pool table. I studied hard and was full of an almost apocalyptic vengeance.

I was a nobody, an embarrassment and dreamed often of destroying the entire town. There was a nuclear power station 15 miles away and it was my recurring dream that I would laugh at them all as they were turned to dust in the mushroom cloud.

Then something amazing happened: puberty. All of a sudden the bullies had voices breaking between falsetto and basso and the girls laughed at them, not me. In that time when they fell, I learned a simple thing: just one word at a time. How to win over the girls with a sly, wry observation. The playing field was levelled and, being a late developer, I had the advantage. I pointed at my enemies and said "dork" and the girls laughed.

Twenty-five years on, I have finally forgiven my grandfather and father for the legacy they passed on to me. I see the positive in stuttering. What psychologists are not allowed to say is that in stuttering there is a kind of rebellion. My father's stutter was the only weapon he had against his mother's rule. Mine in turn had been against the world my father had brought me into.

In many ways I still do what I did then with my little one-line snipes against the world. I no longer stutter, but maybe still speak from the position of the angry outsider. I no longer fear words. If anything, I have overcompensated. But if there is one thing I have learned from stuttering, it is that a single well-chosen word can expose hypocrisy. The nuclear cloud has gone, but I am still wreaking my vengeance against those who think they know what they are talking about, those who believe everyone should think and talk as they do. The silent suicidal boy is still by my side, urging me on.

In my years learning to cope I uncovered a fact that I find ironic and redemptive: in the 19th century, anthropologists and linguists scoured the world to find the origins of the stutter. There was a tribe in Africa that was rumoured to suffer from it. On discovering the tribe, the scientists found that the source of the condition had been a Christian missionary who had taught them English and the words of God. I like to think that my grandfather, had he lived, would have smiled as he told me that story.

Cured as I am, the one thing I will never do is tell my son of our family history of stuttering, for fear that it will, in turn, put the fear of words into him. He is of the age now that I was when I first stuttered, but I would rather spare him the rage I have lived with. The rage that nearly destroyed me and then, ironically, saved me; which has turned me into the man whom he calls, without question or fear, Dad.

· Ewan Morrison's new novel, Distance, is out on Thursday. His first novel, Swung, is now available in paperback.

· Do you have a story to tell about your life? Email it (no attachments, please) to my.story@theguardian.com. If possible, include a phone number