Ultimately, given the data and the market, the REAL consideration is: First, what type of book are you writing? (booklaunchers.com)
There are certain prejudices in the book market that assume that certain types of books are written by one gender or another. (jeanettecates.com)
Determine what type of book you are writing, how many words it will contain, when you plan to publish it, and the money available to fund the development and marketing of the book. (bookmarketingtools.com)