Autobiography; Coming of Age; Family Drama
What, you may be wondering, is the difference between autobiography and memoir, and why can't you just call Stitches a graphic novel? Well, it goes something like this: Novel means fiction, so even though this book looks like a graphic novel, it's actually a graphic memoir.
Both autobiography and memoir are about the author's life, but autobiographies are usually chronological accounts from birth to the present, while memoirs focus on a narrower period of time. Stitches falls somewhere between the two, given that it starts when David is six and ends when he's thirty (with a recent dream providing a kind of epilogue.) The cover of the book says "a memoir" on it, so that's a pretty solid clue, too.
As for the coming of age part, David literally comes of age in this book, growing from a six-year-old navigating a difficult family life to an adult who's finally broken free from his childhood constraints. The coming of age genre usually sees young people sorting some important stuff out for themselves without adult guidance, which is definitely the case for David in this book. Heck, nobody even tries to guide this kid.