I recently edited Discord's Child again (the new version is online now), and for the first time I used the proof-read feature on my computer.  It was worth doing.  Every time you make changes to a manuscript you run the risk of making new mistakes, and the more familiar you are with the work, the less likely you are to notice them.  
The computer proof-reader spotted several instances where I'd removed a word and left an extra space, and drew my attention to a tendency to repeat certain phrases.  However, it also kept suggesting that if I'd put a question in direct speech I should use a question mark at the end of the speaker's phrase e.g. "Is that the time?" she asked?  Each time I used words such as king, maid, boy, girl etc. it suggested I should use something non-gender specific instead such as monarch, servant or child.  Ludicrous! 
 There's nothing intrinsically wrong with gender specific terms as long as they refer to a specific person, and in languages other than English, such as German, they are used far more e.g. Arzt/Arztin = doctor, Freund/Freundin = friend.  Sometimes this is clumsy, but often the gender specific term is essential for clarity.  What's wrong with being called an actress rather than an actor, or a heroine rather than a hero, unless you feel being female is somehow inferior? Where it is unwise to use a gender specific term is when referring to a 'role' in general, which might apply to both men and women e.g. chairman instead of chairperson or headmaster instead of headteacher.
In short, the proof-read feature on a computer is useful, as is the spell-check, but it isn't always right.  Like a human proofreader, it only makes suggestions and it's up to the author to decide whether to follow them or not.