Perfect pitch is for life
It may fade but can be brought back to the front by using the skills. So it is a wonderful thing to teach children. It is rare mostly because people dont know how to teach it to children and it is much harder to acquire as an adult. It is possible to aquire perfect pitch as an adult but like we are finding our kids are beating us to it
To obtain perfect pitch as an adult requires consistent and regular exposure and some left brain effort. To teach it to children just requires regular exposure to named "perfect pitch" notes.
I didnt learn it as a kid but I am certainly developing it by using soft mozart and Little musician. I can identify chords DO ME SO, FA LA DO, and individual notes DO, RE, MI, FA, SO with about 95% accuracy now. DO, RE and MI I learnt from soft mozart but the chords I learnt from Little Musician. Having a focus on note pitch is making my middle daughter pick up piano pieces much faster than my oldest daughter did. Very useful. (save a fortune in lessons if you are paying for them!)
Oh and they all sing in key more now too.
Those whos kids struggle with soft mozart guess key game. Have you tried pressing the notes keys for them? Sometimes my son plays and all he does is listen and call out the notes. I press the keys for him. He is still gaining the listening skills without the pressure, and at a faster rate than Little Musician teaches the notes.(including base cleff!) Eventually when he is confident enough with the note pitches he will be able to add in the keyboard. Personally I am happy for him to just use the gentle piano part of the program for now. After all that is what I wanted him to learn from it - how to play piano! We have Little musician for the rest now