why do authors use initials instead of full name?

When Cuts Like a Knife was first introduced, my sister Susan asked me, “What’s with the initials on the cover of the book instead of using your full name?”

My first response was it seemed to have worked out fine for Joanne Rowling—and no, no one has been able to confirm whether her middle name is Kathleen or Katherine. (Do you know why?)

 That raises a bigger question then why I went with M.K. rather than Mark. Why did Joanne become J.K. To my knowledge she’s never answered that question directly.

So I’m left to assume that she used initials to make her author name gender neutral, which sort of makes sense for the launch of a series categorized as children’s literature.