I have Firebase Analytics integrated into my mobile apps (Android and iOS). Every mobile user has a unique ID that is used to set up the Firebase SDK with. Is it possible to find out age bucket and a gender of a specific user? I've been looking at User explorer on Google Analytics console but could not find a way to connect user ID and age/gender.
Is it possible to find out age bucket and gender for a specific user?
No. As per https://support.google.com/analytics/answer/2799357?hl=en#thresholds
Thresholds are applied to prevent anyone viewing a report from inferring the demographics or interests of individual users. When a report contains Age, Gender, or Interest Category (as a primary or secondary dimension, or as part of an applied segment), a threshold may be applied and some data may be withheld from the report
So when you try to combine the User ID with demographics data, each row in your report contains info about only 1 user, which is below threshold, thus demographics data gets hidden.
If you need user-level precision for gender/age etc... with Firebase/GA, the 2 ways I see are:
You save that data against each User ID in user properties / custom dimensions so you can retrieve it at will.