To enable the camera in MIUI to autodetect the gender and age of the photograph subjects, go to:
1. Camera –> Swipe right –> settings (at the bottom) –> turn on Face detection (pictured above)
2. While in the Age and gender settings, turn on ‘show age and gender when beautify is on.’
3. Go back to camera, choose selfie mode, at the bottom, the star icon, choose to turn on the beautify mode (low, mid or high).
You will now be able to see age and gender in the selfie cam!