I guess the author can also be a female, can't he? :)
They most certainly can! I've added both "her" and the gender neutral "their"
Why "their" ? cause the author is one person, and hence can't be "they". So it can't be "their" !
"They" (and related pronouns) is used for when you don't know the gender of a person or they don't relate to any particular gender
In common English, though not agreed by everyone, "they" can be used for singular gender-neutral 3rd-person.
I used 'author'and I was marked as wrong, it only accepts 'writer'
Author is accepted. If it is not accepted when you write it, please report it via the report button. The sentence discussions are not for reporting.
Thomas Wolfe comes to mind.