All TMNT characters are copyrighted by Mirage studios and were created by Kevin Eastman and Peter Laird. And this is a non-profit fanfic. So on with the fic.

A little secret

Donatello had been going through the charts for days, still hoping to find a mistake, if he was going to break the news to his brother, he'd better be sure of it or he would pay it dearly.

Donnie really wanted to smack himself for even looking at the information and he knew he should be careful to keep this information to himself for he could already imagine Mikey's and Raph's reaction to it. And he was quite fond of having his head attached to his neck, no matter how much self-control the affected turtle he had been examining had.

He decided to talk with Leonardo one quiet evening when he was certain Raph and Mikey were out for the night and master Splinter was in one of his yearly pilgrimages somewhere.

Leonardo was meditating in the middle of the dojo with his eyes closed. To the non instructed eye he looked exactly as the rest of them, which had made Donnie doubt about the profile he had been looking at, but lately the differences had started to become more obvious: the flat plastron, the shorter and thinner tail, Don blushed with guilt, the sudden growth spur and that rare to non-existent need to cut his nails that had alerted Donnie of a possible dietary deficiency and had led to the full checkup.

As soon as Donnie stepped on the mat, Leo opens his eyes and gave Don an eerie look. "So how did I do?" he asked, closing his eyes again ready to take any news with his mind clear.

"Leo I need you to come to the lab, I... really need to talk to you." Donnie said, looking at the floor and playing with his fingers.

"That's bad hm! Am I mutating again?" Leo asked

"No, you aren't sick!" Donnie promptly replied, "but still I need to talk to you'', and preferably not here, he thought, wanting to have this talk as far as possible from anything keen or sharp.

Once in the lab Leo had taken a seat and was curiously looking at Donnie's fish tank which provided cooling to the massive computer because, for some reasons, Donnie refused to meet his glance, therefore, he focused his sight on the fish tank instead.

Finally, Donnie cleared his throat. "Leo, have you ever felt something wasn't right?"

"We are the result of an accident induced by an alien mutagen; of course I know something is bound not to be right." Leo calmly replied.

"Well yeah," Don said, hoping Leo would get the hint. "But with you, have you ever wondered why you need to work twice as hard to keep up?"

Leonardo scratched his head: he certainly had to work twice as hard as Raph and still, he was nowhere near his hot-headed brother's strength, but he had skills and that always gave him the upper hand so he had never really lost any sleep over it.

"Well, we all know I was not the healthiest as we grew up" Leo replied, trying to explain it.

Now it was Don the one scratching his head. This was not going to be easy.

Leonardo looked at Don's distraught face and decided to end his pain.

"Don, please, come straight to the point. I am a big boy I can handle things"

Donnie broke in a nervous giggle. "Yes sure… big boy"

Leo sighed. He had been trained to be a warrior, dying or whatever was part of the contract, and he knew Donnie was not one to beat about the bushes, so he really did not get Don's attitude and it was beginning to annoy him.

"Well… about the big boy part?" Donatello replied.

"Donatello!" Leo finally snapped trying to make his brother talk straight.

"Well you see, we all were, in the beginning normal healthy babies of the Trachemys Scripta elegans"

"So we are red-eared sliders etc." Leo nodded. He was not really keen on biology but he knew that at least, so he turned his eyes from the fish tank and met Donnie's eyes. "Why am I getting a biology class?"

"As a matter of fact, you should get one." Don said quietly averting his eyes again from Leo's inquisitive stare.

"You know we are different from humans, right?" Don continued

"Really…?" Leonardo said sarcastically, "and what gave you the first hint the green skin or the shell?"

"Well, when master Splinter found us..." Don gulped. " He really did not know much about turtles, for which we cannot blame him because he was a pet rat, not a reptilian biologist and even them have some troubles with the traits in young reptilians, I mean for snakes they basically have to surgically verify and…"

"Donatello!" Leonardo said again in an angry tone interrupting Donnie's monologue.

"Well basically you are not a…" Don gasped. "Er…have you ever considered changing your bandanna to another color? I don't know maybe a pastel color? A p... p... p…ink one?"

Leo stared at Don for a minute not fully getting the implications of Don's words: why on earth would he switch to a pink one? Blue was a good color, which Splinter had chosen for him, but he really did not care about it. He looked at Don's bandanna. Maybe Don wanted to trade his purple bandanna for a blue one. He could not blame him: that color was a difficult one. He was fine either way; though if he had a choice he would go for a black one, yes midnight black seem cooler and a lot easier to get than the blue color one. He even had talked to Master Splinter about it, who had adamantly refused.

He finally voiced his thoughts. "You can have the blue color if you want, I'll even talk to master Splinter about it, but I must warn you I have not been very successful in my quest for a black one, I guess master Splinter still has trouble distinguishing us without the color reference," he smirked pointing at his bandanna.

Don returned the laugh painfully, shaking his head. "Leo, you really don't get it right?"

"This talk is turning weirder than those with Mikey. Yes I really do not get it" Leo said calmly, when suddenly the tone choice implications stroke him as the proverbial anvil falling on the head of the character in those cartoons. He shook his head and shivered. No Donnie could not possibly be talking about that; he must have misunderstood something as he certainly did not feel any inclination to paint his room in pink and start collecting ponies, ballerinas or whatever but then... he really wasn't human so he did not know, but certainly he would have noticed before, have suspicions of any kind. He shook his head again making his mind go blank and raised his gaze.

"Donnie, would you mind speaking your mind in plain simple English, please? No more circling around." Leo said in a collected voice.

"You were different from the rest of us from the beginning…" Don stopped.

"Different species perhaps?" Leo said. "That would explain a few things." Such as why he was leaner, had more trouble gaining muscle, had grown slower.

"Almost right, but no, what I mean…is you were…" he gulped. "I mean you are like we are: a mutant trachemys scripta elegans yes... but unlike us you are… a female one."

Leonardo was caught in a hysteric laughter. "Yes... sure. And Mike is the Cheshire cat, Raph is going to wear a tutu for his next night round with Casey and I forgot it is April's fools! You almost got me Don" he prepared to leave when Don's face told him he was not really joking.

"Ok, you are serious." Leo gave Don a deep glare.

"Positive." Don nodded.

"You are sure Klunk did not mess with your papers again or Mike hasn't been playing with your computer?"

Don was upset that Leo was questioning his knowledge. 'He'… ugh… Donatello wanted to scream… had always trusted him. "No I double checked... five times. I am the one here with chelonian knowledge worth a PhD and you are questioning my expertise?" Donnie met Leo's surprised eyes.

"You truly did not know? You did not even suspect a thing?" Donnie asked.

"I never really thought about it, I am not the one with a soap opera obsession like Mike or a hormone-like driven temper like Raph," Leo said. "But whatever," he said calmly.

"That is all you want to say?" Don replied.

"There is nothing I can do about it, right? Well maybe now I can feel at ease singing 'I feel pretty'," he said with an evil tone and approaching Donnie looking at him straight into the eyes and tapping his plastron, she added "but I would rather this be our little secret, one that will get you disemboweled should you ever mention it again." Leo said with a deceiving smile that froze Don to the bones as Leo left his lab.

"Whatever you say," he said, embarrassed to notice how beautiful… err… Lea? truly was and having to reconsider about the aggressiveness level the females were said to possess.

Author's note

Ok Leo's fans please don't kill me. I am a big fan of the TMNT, particularly of Leonardo. I have all the movies, love both the old cartoon and the 2003 one not much into the Fast Forward though (I cannot see Leo's improvement anywhere and he already trained with the Ancient one and the tribunal). As I've never been much of a comic fan, the turtle comics have always strike me as difficult to read.

I had the idea for a while: determining a reptilian gender can be really tricky before they reached puberty so I wondered how Splinter found out and I have restrained myself but after reading a fanfic where Leo is exposed to laughing gas and sings the "I feel pretty" song I just had to write it.

The characteristics I describe fit those of the read eared slider morphological differences: once they mature females are larger and have shorter nails.

Special thanks to the official Beta of this fic, Lady-Kassy for revising this chapter.