How to export stems as they ARE

I have mono and stereo tracks in my arrangement. I need to export all stems to send to a mixing engineer. But when I do Cubase exports all my mono tracks as stereo! What’s the secret to exporting all tracks AS THEY ARE so stems are both mono and stereo as they appear in the arrangement?

Do you have Cubase Pro 11 or newer?

Then you setup a job in the queue in the audio mixdown dialog for the stereo tracks and another job for the mono tracks.

In this case it’s well worth consulting the manual. It shows how the various settings in the Export Dialog interact and what their impact is on stuff like Stereo vs. Mono.

Yes I have 13. So there’s no way to do it with just one operation??

You can try if the following suits you better:
Select all tracks that you want exported in the project view but make sure there is no event/part selected.
Menu Edit → Render in Place

This is not stem exporting, however, but only tracks output with possibly effects on them.