It's an exaggeration but there might be some truth in it. For example, J. K. Rowling was advised by her publisher/agent to use those initials rather than a firs

It's an exaggeration but there might be some truth in it. For example, J. K. Rowling was advised by her publisher/agent to use those initials rather than a first name because a feminine name would have discouraged boys from reading her books. On the other hand, I read somewhere that a lot of romantic novels (Mills & Boon, etc.) are written by men using a feminine pseudonym so probably someone should check the stats to see if there really is an asymmetry here.