In a city where the kids are raised and taught by robots so they don't know about genders till they get them. A class was told big changes would be happening soon. The class were all friends for most of their lives. The kids kept growing but never knew the gender male or female so when their time comes they'll turn into their proper gender.
In a dorm room at night two roommates were in their pajamas. One named Joe and one Sa. Sa asked "So we kept getting told about a big change. What do you think it's going to be about?"
Joe in bed said "No idea let's go to bed and get to sleep. Whatever will happen when it happens."
Sa getting in bed said "I suppose we should sleep... I do feel a smidge odd though." Then Sa shed it's pajama shirt before sleeping. Joe thought it was an odd habit but there was nothing weird about it.
Joe getting drowsy said "If your getting a cold then your in quarantine." Then the two friends went to sleep. In the middle of the night Joe got up and thought "Ugh... I guess i'll go to the bathroom... I think it feels like I need to go to the bathroom anyways." Thank goodness for every pair having their own bathroom. Joe pulled down it's pants and then sat down on the toilet and when Joe tried to urinate Joe looked down and saw that at his crotch was something out of his pee hole. It looked kind of like a pink mushroom, curious Joe poked it and withdrew his finger at the sensitivity of the head of Joe's soon to be penis. It pushed out further slowly and then Joe's testicles started coming out.
Joe got up and then then noticed that he was taller and looking in the mirror saw that his face changed a little. His shirt felt a little tight as his upper body had grown slightly larger. Going back into the bedroom Joe said "Sa wake up. Something's happened." and noticed his voice was a bit deeper and turned the light on.
Sa was snuggled in it's blankets and a muffled voice said "Go to bed..."
Joe said "No seriously Sa look what's happened to me. I'm bigger and this thing came out of my crotch."
Sa said "Just another growth spurt and that thing's urine."
Joe irritated went to Sa's bed and grabbed the blanket and then said "No look." with his hips and groin thrust higher to where Sa would see. He however saw that Sa had changed a bit as well. Sa's body seemed to have slimmed and became more slender except for Sa's chest area. It was puffy and rounder and Sa's face seemed more cute.
Seemingly irritated Sa said "Get your pee... stick... out of my face! You may have changed but we'll just ask our teacher about it latter." Sa turned the lights off then went back to her bed. Sa tried to get back to sleep and then...