Chapter 1: Discovery

Donnie was baffled to say the least.

This morning he and his brothers had decided to see if they were related by blood or not so Donnie took their blood to test. It turned out none of them were related by blood but that wasn't what shocked Donnie.

He'd gone over the blood samples time and again.

But so far it hadn't done much to help him understand what he was seeing. It had to be a mix up with the samples, or something similar to that. He just couldn't get his head round it.

A sudden knocking sound snapped his train of thoughts.

"Hey, Donnie. Can I come in?" A voice asked. Donnie looked up from his microscope and saw April in the doorway holding two hot cups of coffee. "Oh, hey April. When did you get here?" He smiled.

"About ten minutes ago." She replied as she made her way into the lab.

After giving her friend his drink she noticed his puzzled look as he stared at the microscope on the desk. "Something wrong Donnie?" She asked. "I just don't get what I'm seeing here April. I've lost count of how many times I've redone these tests, but the results are still so, so…I can't find the word for it." He admitted.

"What's the problem?" She asked, walking over to him.

"Take a look at this theses samples from mine and the guys' blood." he said, nudging the microscope in her direction. Looking through the eyepiece, she saw exactly what Donnie was talking about.

"Oh my god!" She exclaimed as her eyes going wide.

"Donnie, do you know what this means?" She asked. "I think I might do, if I've got the right chromosomes." He mumbled. "Well, I don't know as much about turtles but I think I know enough to understand what this means." She explained.

They were still taking in what they had found when another thought came to her mind.

"Who's sample is this Donnie?" She asked nervously. "Leo's. I don't know what I'm gonna tell the others though. I'm not even sure how's best to approach it." He groaned.

This was so hard.

"I think we should tell them tonight. Leo said earlier that Mikey had almost finished cooking dinner, so if we wait until afterwards, then we can get it out in the open and over with." April said.

"You sure that's a good idea?" Donnie asked.

"Yes. The sooner we tell them, the better."...

Dinner that night was somewhat awkward. While Raph tried to hit Mikey for pranking him earlier and Splinter ate his own food in silence, as usual. Leo could tell something was up with Donnie and April.

April was repeatedly looking at him funny all the way through the meal and Donnie wasn't looking at him at all.

Instead he was looking down at his food, which he'd hardly touched. This really concerned Leo as his brother would normally engage him in conversation about almost anything while he enjoyed his food.

Master Splinter had also noticed their strange behavior. But what Leo hadn't noticed was the knowing looks the two kept sending each other across the table. The rat could tell that they were hiding something, but he decided not to pry.

He trusted that his son would tell him what was wrong when he was ready to do so...

After dinner, the group gathered in the living area once more, and began to play a game of Snakes and Ladders. After Splinter had managed to win the game twice, April and Donnie decided that now was the right time to talk to the others.

"Hey, guys? Can we talk to you for a minute?" Donnie asked cautiously.

"Sure thing D, what about?" Mikey asked as he stopped rolling the dice. "April and I found something in one of the blood samples. We really think you need to know about this." Donnie confessed.

"Is something wrong?" Asked Leo.

"Yeah, none of are sick or anything are we?" Asked Raph. "No, don't worry. It's nothing like that." April assured them. "We just found something important we you should know. But it's not dangerous." Donnie added.

"OK... So what is it?" Leo asked.

Donnie wasn't really sure where to start with this. So he decided first to see how much his family could already understand. "Well, what do you guys know about chromosomes?"

"Aren't they the things in cells that contain genes?" Asked Leo.

"That's right, Leo. Do you know anything else?" He asked hopefully. "Well, I know that each one's paired with another, so there's always an even number of chromosomes." Leo replied.

"Yeah, that's right." Said April

"There are two types of chromosomes that determine a person's gender. A girl has the pairing XX, while a boy has the pairing XY." Donnie explained. "What's that gotta do with our blood samples?" Asked Raph.

Donnie took a deep to calm himself down before looking up to his family once more.

"It's Leo." He said at last. "When I looked at his sample, I…I found that his sex chromosomes didn't have an XY pairing." He explained

The statement left his family in silence. He couldn't be saying what they thought he was saying, could he? "Leo has an XX pairing." April confirmed. Everyone was quite obviously shocked at what they had heard.

Raph's mouth was hanging wide open, while Splinter's fur was standing up slightly.

Mikey's eyes so as big as dinner plates. The three of them slowly turned to stare at Leo, who was now silent and un-moving, eyes slightly enlarged. After what felt like an eternity, Mikey broke the stunned silence they were in.

"S-So, so t-that means…" He stuttered and Donnie nodded.

"Leo's a girl." He said. Leo looked at him and she could tell that he was telling the truth. "A-Are you really sure Don?" She asked slowly. "Sorry, Leo. I've double checked the samples dozens of times today. You definitely have an XX pairing in your cells." He sighed.

"But how come we never noticed?!" Cried Raph.

"I don't know Raph." Donnie bit back before taking a deep breath. "The point is, chromosomes aside, there's more than enough evidence to prove what April and I have found to be true. Leo is definitely a girl." He explained more calmly.

Before the others could say anything, Leo began to walk away.

"I'm gonna go to bed. I'll see you guys in the morning." She muttered. "I just need to think about this for a little while." She added and with that the blue turtle went into her room, leaving her brothers and father to themselves...