Learning to write starts with learning a language. The environment in which people are raised influences development. People are not born with any communication skills beyond crying. They can't even write "WAAAH!" Babies learn to talk in their home and daycare environments by listening to parents and caregivers. At an early age, humans have a capacity to learn language that is lost as we grow (which is why my toddler already knows more Spanish than I do). As Ayn Rand writes in her book The Art of Fiction, "Language is a tool which you had to learn; you did not know it at birth. When you first learned that a certain object was a table, the word table did not come to mind automatically; you repeated it many times to get used to it."
Research shows that children in poverty are exposed to fewer words than their peers in high-income households and have significantly lower vocabularies. By the time they reach school, these children have catching-up to do. It’s not fair to classify people from privileged homes as “born writers.” Being exposed to a wide range of words from a young age does shape vocabulary, and might produce better writers, but they are no more born to write than people who grew up in poverty.
Just as children aren’t born writers, they aren’t born readers, either. Children need to be read to, they need to be surrounded by books, they need to be engaged with text in their environment—all before the age of three. Without a proper, stimulating environment, potential can be wasted.
I hope that anyone who considers herself a writer reads widely and varied. Authors don't have to have an MFA in creative writing; although, it doesn't hurt. We learn how to write—how stories are told, how dialogue works, etc.—by reading what others have written. As author John Green put it: "I really think that reading is just as important as writing when you’re trying to be a writer because it’s the only apprenticeship we have. It’s the only way of learning how to write a story." Avid readers make better writers, and those writers are influenced by everyone they have ever read.
To call someone a “born writer” is a disservice to his grade-school writing teacher. She had to read his fledgling attempts and find ways of improving them. All authors went through a period of substandard writing when they were learning. The idea of being born a writer deflates the aspirations of a young people because they aren't good at it, yet. I don't want today's students thinking they'll never be a writer. Author Maureen Johnson has something to say about that: "Let me let you in on a little secret. When you are learning to write, you are going to suck. You are going to suck a lot. You're just going to keep sucking for a while, and you're going to feel like you're sucking and actually that's a sign that you're completely on the right path because when you are learning things, you suck at them."
The more people write, the better they become. This is why there are creative writing classes, MFA programs, and sections of the bookstore dedicated to writing prompts and exercises. Neither J. D. Salinger nor J.K Rowling came out of the womb knowing how to write. It took practice and mistakes and writing and rewriting to refine the craft.
People are born with the potential to achieve greatness. And some people are born with a higher potential than others, but calling them “born writers” discredits everyone who helped them along the way. Writers are made, not born.