"Sarah-Jane, is your name and you are very definitely a girl, now, you want to know why, right? Here's the truth"
"As you know, Ms Esposito is my bestie Tiffany's aunt, and, as I am sure you are aware, Tiffany has a real problem with her sex drive, so much so that it will likely ruin her chances of a good future, Tiff's aunt is a scientist, an expert in DNA and she is also a practitioner of what some would call Witchcraft, now the latter I'm not so sure of, however, given the obvious evidence, my opinions on that are subject to review. Dr Esposito is , in fact, working for my dad, her research is brilliant and can provide real medical benefits for people with genetic disorders, it can cure Tiff, it can fix things like diabetes and cancer and it can also correct people's chromosomes so that they can be the gender or sex they feel they should be , and back again if they feel they made a mistake, now, this means that Trans people can be who they want to be, it means Tiff can have a life and , Jon, for people like you and Trinity Blake and my cousin Helena, you can be who you want to be..."
Sarah looked meaningfully at Sarah -Jane, internally the Sarahfied Jon was panicking She knows, Oh God she knows! How? I was so careful, I've buried these feelings so deep now , how...oh, now I remember
Cut back 13 years, and we see Pre-school Jon, Karyn and Sarah in Sarah's room, the girls want to go swimming in Sarah's pool but Jon hadn't brought any trunks, being very young he saw no reason to spurn Sarah's offer of borrowing one of her one piece suits, he chose a pink one and the three children went to play, they had fun, this was often repeated until one day Sarah's mom came home early and not knowing who the child with the pink swimsuit and the longish brown hair was, mistook Jon for another girl, Jon was embarrassed, but afterwards he told Karyn and Sarah how he wished he was a girl like them so he could wear pretty things like them. Jon had thought this to be long forgotten but the reality was, both girls remembered it, Sarah had taken it to heart because she had a trans cousin and later she remembered Jon's words and put two and two together, she believed Jon was like her cousin Hector, now going by Helena,
"So, Sarah-Jane, there are three options, you were chosen at random, but I think this is Fate giving you a chance, firstly, after a month and we have proven the process is stable, we can restore you to your original male self, no harm, no foul, second option, you stay exactly as you are now and you become my twin sister in every way that matters - just think, beauty, brains, popularity and wealth, you need never worry about anything ever again, thirdly, and, I believe this is the one you will go for, you are restored to the female version of your old self, with, maybe some upgrades or tweaks - once we prove this works, then the other trans kids in school will be offered the same treatment , so you would be helping out them as well and we will have proven that the process works and we can move onto helping out Tiffany too, this is a hard ask but if you stick with it and co operate, then millions of people all over the world will lead better lives because of you - surely being my twin for a month is a small price to pay to help out so many others?"
Jon thought about it, there was no doubt that being Sarah 2.0 for a month would be interesting, also, being a girl filled her with such joy that she could not deny the many benefits to this strange transformation, and then there was Karyn, Jon had struggled with asking Karyn out, she was bisexual with a strong preference for girls, being the hottest girl in school would only make getting Karyn's interest easier, and after what she and Sarah had just done and how she felt regarding her life long friend, she was pretty sure that as Sarah Jane, she was still into girls.
"Alright, Sarah, you have a deal, but, I want to ask Karyn out , so you need to call a truce with her, whatever dumb feud you have ends now - deal?"
"Definitely! I have wanted an excuse to finish that stupid argument for years, I'd love it if you two got together, so, shall we get going, it's almost lunchtime, I hope you are happy to sit with my friends, you can invite Karyn if you like, she's cool"
The two set off, it was surprisingly easy for Sarah-Jane to slip into the role of a pretty girl.