The singular "they" is grammatically correct and requires less effort than "he or she" or alternating "he" and "she".

The generic "she" isn't gender-nuetral, but I think it's fine to use when everyone else is using the generic "he". Like affirmative action for pronouns. I usually use "they", but whenever I see an animal and I don't know it's gender I call it a "she". Because most people will call the animal "he" and I want to counter-act that.