Every reader is drawn to a particular type of genre. Most hardcore readers read just about anything you put in front of them, but we all have a favourite calling when it comes to books.
Where did you get that book?
I suppose that your choice of genre is influenced by the type of book you first read. Whether you have a built-in appreciation for a type of genre that is fed when you find the your first book that interests you, or the first book you read plants the seed is a topic for debate.