The idea is to have a sophisticated calculation methodology based on username, full name, bio, image captions, comments and commentators. Each section would hold a different weight and the system would learn over time and improve its guesses.
This is how things will work;
1 - You upload;
The system returns;
ig.com/username1 - 80% male 20% female
Most of them would have imbalanced ratio to clearly indicate what the gender of the profile is. Things get tricky with business accounts but moving forward, the system should also learn to indicate and differentiate between personal and business accounts.