"Now, according to my calculations, the genetic feasibility of successful procreation between human and mutant turtle is astronomically low.”

“Astronomically low,” repeated Dani.  “But not impossible…  Right?”

Donatello sighed, rubbing a hand over his face.

“Scientifically, nothing is one hundred percent impossible,” he said.  “But that doesn’t mean we’ll see it in our lifetimes.”

That was not the answer she wanted to hear.  She crossed her arms and walked over to the couch in the corner, sinking onto it as her mood tanked.  With a sympathetic frown, Donatello walked over and crouched in front of her.

“You’re not upset with me, are you?” he asked.  She shook her head, but remained pouting.  He squeezed her knee, trying to get her to look up at him.  “Hey.  I never said I wouldn’t keep looking at the data for you.  After all, my brothers and I were once considered scientific anomalies too.”

He waited to see if she would react to that, but to no avail.  She was too crushed by the statement he’d made previously.  He supposed it was his fault for getting her hopes up.  He’d boasted that the mutagen infused human DNA into his turtle DNA, and when she asked if that meant they could make babies, he didn’t dismiss the topic entirely.  After all, he was a scientist.  He liked knowing the facts before discounting something.  Though his kind was genetically similar to humans, they obviously weren’t a match.  They had less in common with humans than monkeys.  The two primates shared roughly 98% of their DNA, but they still couldn’t reproduce by natural means. 

After patting her leg, he stood up.  “It’s late.  You should crawl into bed.”

She nodded, accepting his hand to help pull her to her feet.  He wrapped his arms around her when she was up and kissed the top of her head.

“I’ve got to tidy up in here,” he said as he let her go.  “I’ll be right behind you.”

With that, Dani left the lab and Donatello by himself.  Once alone, he sank down onto the couch with his face in his hands.  He had to admit, the data was disappointing to him as well.  As silly and irrational as it may have been, he had allowed Dani fill his head with thoughts of them having a little unconventional nuclear family of their own.  He didn’t want his disappointment to make Dani feel worse, so he tried to keep a clinical façade when explaining everything to her, just presenting the facts with no emotions attached.  Maybe she would have taken it better if he explained it to her as a lover instead of a scientist, but hindsight is 20/20.  Her lover was a scientist, and he was one that saw answers as new questions.  He wasn’t going to give up so easily.  He was more determined than ever to give her a better result.  He rose from the couch and walked back over to his computer.  There was just one thing he wanted to check before he joined her in bed.

💜💚💜

The following days saw Donatello spending countless hours in his lab, even more than customary for him.  He barely ventured out to eat or even sleep.  Anytime anyone went to check in on him, he was always studying data on his monitors or looking at microscopes, then scribbling notes down in a journal and occasionally walking over to his whiteboard to do some math there.  All questions were met with terse responses, no matter who asked.

“Geez, what crawled in his shell and died?” Raphael complained, after getting brushed off by his younger brother yet again.

“It’s my fault,” Dani sighed, looking guilty as she eyed the lab.  “He’s in there trying to slight nature for me.”

“Slight nature?” Leonardo asked. 

She rubbed her arm, not wanting to get into the details of their personal life.  They had kept their talks about the future confidential, not feeling the need to discuss it with his brothers and further complicate things.

“I think you owe it to us to spill, Dani,” Raphael said.  “What’s got the brainiac all worked up?”

After hesitating, she eventually spoke up.

“… He found out we’re not genetically compatible and is trying to find a way around it,” she mumbled.  “You know how obsessed he gets with stuff like this.”

“Genetically compatible?” Leonardo said.  “You mean…”

“Oh, my God, dude!  You two are trying to make babies!” Michelangelo exclaimed.  Dani shushed him as her face went beet red.

Raphael raised his brow ridge.  The corners of his lips twitched as he tried to force down a smirk.  “… Don wants to be a daddy that bad, huh?  Damn, never knew he had it in ‘im.”

“Bom chicka wow-wow,” Michelangelo said, paired with a slight thrusting motion that prompted Leonardo to smack the back of his head.

“Please don’t grill or tease him about it,” pleaded Dani.  “It’s a sensitive topic.  He tried not to show it, but he took it personally.  I think he’s more upset about it than I am.  I told him it didn’t matter that much, and that we could figure something else out, but he’s insisting he’s right on the cusp of a breakthrough.”

A somber silence fell among the group.  Donatello was easily the most sensitive.  Though they hadn’t known about the baby thing before, they knew how much his relationship meant to him, and if he thought it was a roadblock, he would stop at nothing to find a way to give Dani what she wanted.

Leonardo sighed.  “Dani, there’s no way he’s at full mental capacity when he’s not getting enough rest or sustenance.  It could lead to a careless mistake or oversight.  For the benefit of his research, I think we should intervene.”

She wrung her hands.  The last thing she wanted to disturb Donatello, knowing how frustrated he got when he was taken from his work, but she understood that it was for his own good.  She eventually nodded.

All four of them filed into Donatello’s lab, who was too focused on dripping a pipette with a milky clear substance into a flask filled with a mysterious green substance to acknowledge them.

“Yo, Donnie,” Raphael said.  “Ya got company.”

“Busy,” he replied without tearing his eyes away.

“Donnie, can you put that on hold for a minute?” Dani asked, to which he shook his head.

“Dan-Dan, I’m in the middle of something,” he said, voice taking a sweeter tone when responding to her.  Raphael sucked his teeth at this.  “You shouldn’t be in here without proper gear right now.”

That statement had all four of them taking a step back closer to the door.  Their concern was starting to grow.

“… What is that, Donnie?” Dani asked.

“Serum.”

“What kind of serum?”

“Hopefully a mutagenic agent that will adapt your eggs to be able to successfully bond with my—”

“Whoa!” Raphael interrupted.  “Nope.  That ‘hopefully’ ain’t sounding too hopeful.  Put that down right now.  We don’t need you making any crazy mad science on an empty stomach.”

“Get out of here, Raphael,” Donnie snapped, finally looking away from his experiment over at the group.  “And the rest of you, too.  I could do without the added stress.”

“Donnie,” Leonardo said.  “Dani told us what happened.  We know you’re stressed.  All we’re asking is that you take a break.”

In frustration, Donatello’s fist clenched… with the pipette still in his hand.  The milky liquid squirted into the green one, causing a hissing sound and producing gas.  He put both on the workbench at once, turning away to cough.  Everyone else gasped and covered their faces, but the cloud of gas had already dispersed into the room.

“Dude, what was that?” Michelangelo asked while coughing.  “It smells like our room in spring!”

The youngest turtle wasn’t wrong.  The gas produced had a distinct musky smell. 

“Oh, God,” Raphael rasped while waving his hand in front of his face.  “… I better not be inhaling your spunk, genius.”

Donatello shook his head as he held it before removing his glasses to rub his eyes.  “… It’s a compound created from Dani’s DNA to… to enhance… fertilization.”

His words began to trail off as he grew increasingly breathless.  He shook his head again before raising it and looking over in Dani’s direction.  His pupils were blown wide and his breathing was ragged. 

“Yo, I don’t feel so good,” Mikey mumbled.  “Is it me or is it like… really really hot in here all of a sudden?”

A low growl came from Raphael in response.

“Dani…” Donatello whispered, but it was loud enough to get her attention.  “You should probably… go.”

“Go?” she repeated, confused.  “What?  Why?”

“I…  Ah… I-I think I… may have… m-made a miscalculation…”

As he tapered off, the sound of heavy breathing increased all around her.  She glanced around, noticing that all of the turtles looked dazed and flushed.  A realization began to sink in and she backed towards the entrance of the lab.