Everyone knows men are way better at everything including writing.  The rough and tough male ego can’t fathom women writing the sort of things that would entertain them.  They want to read about manly exciting topics like spies, detectives, soldiers, and killers written by other men. 
It’s this accurate reasoning that leads many authors and their editors and marketing teams to the conclusion that female writers are better off using their initials or pseudonyms on their books so they don’t alienate potential readers.  J. K. Rowling was told having her real name, Joanna Rowling, on the book would make it hard to sell a book about a young boy to young boys.  So she borrowed the K from her grandmother and became J. K. She’s not the only one, E. L. James anyone?
But she showed them.  Even after people realized their beloved boy wizard was the product of a female brain they continued buying the series.  Some, myself included, loved them even more.
Unfortunately, she did such a good job with the Harry Potter series and made so much money she created an abundance of haters.  No one wanted to accept that she could do anything but Harry Potter.   How dare she even try!  When “The Casual Vacancy” was released reviews were overly critical and harsh as if for sport.  “…Willfully banal, so depressingly clichéd that “The Casual Vacancy” is not only disappointing — it’s dull,”wrote New York Times critic Michiko Kakutani It was called needless dark and violent among other things.  Kakutani also criticizes Rowling for a sex scene that wouldn’t count as foreplay to the 50 shades crew.  Needless to say it was not well received or fairly treated.  She could not escape her fame or gender.  But kudos to her for trying, instead of just kicking back and counting her millions.
So after the reception of her first post Potter book, it’s no wonder she chose to release “The Cuckoo’s Calling” under a completely different name.  The initial reviews were good and critics praised the author, whom they believed was a former security expert who previously worked with the Royal Military Police, for creating such a vivid an dark lead character.  But in an over crowded genre the public didn’t really take notice.  It was yet another crime tale.  Alas, sales were about 1,500 before the big reveal.   Of course once word leaked that it was Rowling’s work amazon sales of the book jumped 150,000%. 
“Rowling is reported as saying to the  Sunday Times of London, “I had hoped to keep this secret a little longer because being Robert Galbraith has been such a liberating experience. It has been wonderful to publish without hype or expectation and pure pleasure to get feedback under a different name.” 
She’s right of course.  It was the only way she would have gotten honest feedback and to not scare away the men folk.  It was also the only way her venture into the crime genre would have been taken seriously.  Sadly, she had little choice but to create not just the pseudonym, but also a new persona, Robert Galbraith.  Had the same book been released under Rowling’s name she surely would have faced unwarranted harsh criticism again.  “Presumably Rowling and her publishers decided to go that route because they assumed that acrime novel by a male author would sell better.”