Gender assignment throughout song

Hi, I have been trying for days to get Ai to have a female singing part 1 of my song and then a male singing part 2. No mater what I try a male sing the part where the lyrics are I was a 7 year old girl 🤦 it sounds so wrong I have tried square bracket instructions [GIRL ONLY] I even put it just before lyrics bug Ai thinks it's better and ignores this. Do if you could add a gender assignment to parts of songs it would be awesome