Laravel Socialite Facebook not returning gender

Question

Wondering if you can help me. Im using laravel socialite for login purposes. My problem is that i cant seem to get the users gender in my production env conde below:

 $user = Socialite::driver('facebook')->fields([
            'first_name', 'last_name','gender', 'email', 
        ])->user();

The only difference in the two environments is that my prod env is using facebooks api v3.1 but surely it should still be returning gender?