I remember reading an articles about guys having a high voice and being ashamed of it.
A speech therapist (I think) said it's not about the anatomy, it's about the using.
When testosterone makes the vocal folds grow, the person is still not used to the new size and muscles, they automatically try to speak as they used to before, but their vocal folds is different, resulting in the breaking of the voice.
In their therapy, they helped them use their chest register and reach quite deep voices.
Usually, in puberty, boys probably just unconsciously learn to adjust to their new vocal folds and stabilize their voice, slowly learning how not to sound squeaky.