Only if you can't determine gender. Otherwise, you'd be "what is she/he doing?"
It's usually clear from context. How often do you look two blocks away and see a group of unrelated individuals doing different things to the point "what are they doing" is unclear? Can't say I've ever run into that in my 48 years.
It's usually clear from context. How often do you look two blocks away and see a group of unrelated individuals doing different things to the point "what are they doing" is unclear? Can't say I've ever run into that in my 48 years.