This fic will be a series of one-shots centred around the pregnancy of Stiles and Derek's first child. It does feature Mpreg, so if you don't like, don't read. It's the first in a series called "The Stilinski-Hale Pack". Updates will be sporadic. Enjoy and tell me what you thought.

The scientists had called it, initially, a quirk in biology. Really when a man in the 1800's successfully conceived, carried and gave birth to a baby, what else were they supposed to call it? But when the technology finally caught up with them, they quickly realised it was more than just a genetic one-off. It was a mutation of the genes, causing a male to be average in every way except that they possessed a woman's ability to carry a baby.

What was more, it was soon realised that this wasn't exactly rare either. When compulsory testing had finally been implemented in 1900 it showed that nearly 10% of the U.S population alone carried the gene, and that number was quickly rising. By the early 2000's the rate was up to 40%, making it almost as common as not for a man to be able to carry a child. And that number included one supernatural obsessed, ADHD husband of a werewolf.

"Hey Stiles," Derek called to his husband, eyes never leaving the television screen. He didn't bother waiting for a response when he continued, "Do you want to have a baby with me?"

The question was met with a loud crash, some creative swearing on Stiles' part and finally silence. Derek lifted a foot off the coffee table, preparing to see what the crash was about when he heard Stiles' approaching footsteps and he relaxed back into the worn leather of the lounge. Out of his peripheral he saw Stiles enter the room, mouth open wide and eyes slightly bugging out.

"What did you just say?"

Derek didn't answer. He was still preoccupied with the news report playing on the television. Stiles followed his gaze, eyes widening further as he dropped onto the lounge beside Derek. A bleached blonde reporter with an unbelievably fake tan was droning on the screen, speech jumbled with statistic after statistic and intermingled with scientific mumbo jumbo. Stiles eyes however were caught on the headline emblazoned in yellow across the bottom of the screen.

SCIENTISTS' REPORTS FIND THAT MALE FERTILITY RATES ARE RISING AT A STAGGERING RATE.

Interested now by the report, Stiles focused back in on the broadcaster as she sent a blindingly white smile the camera's way.

"The latest scientific papers track the movement of the mutated gene that allows males to conceive, carry and deliver children naturally. One hundred years ago only 10% of the male population carried the gene but now it is estimated that almost 40% do. Scientists are saying that within the next fifty years the percentage could increase to a staggering 75%."

The anchorwoman signed off with another blinding smile and disappeared from the frame, taking her outrageously orange skin with her. As the news logo appeared and the program changed to a feature on a man who liked to eat plastic bags, Derek switched the television to mute, plunging the room into charged silence.

It was clear now where Derek's seemingly random comment had come from. Stiles has been tested, like every other boy in the country, when he was ten years old and had found out that he was a carrier. That meant that having a baby together was a very real possibility for Derek and Stiles. And the news report only served to remind them of that.

Eight years ago when Stiles and Derek first started dating, it had been entirely out of the question. So out, in fact that Stiles hadn't even bothered to mention his baby-carrying abilities straight away. Not only was he not ready, being seventeen and a senior in high school dating a 21 year old but then, Derek had still been torn apart over the deaths of his family. Still wracked by the guilt of inadvertently causing his family's death that even the thought of starting his own family had seemed like a complete betrayal. Neither of them had been ready so it hadn't really mattered.

Four years ago when Stiles and Derek had gotten married they had been closer, but still not quite there. Derek had come to terms with his family's death; he had finally gotten the closure of losing his pack by forming a new one, developing connections that were almost as deep as his lost familial bonds. But the timing hadn't been right. Stiles had just graduated with a shiny law degree - because apparently thorough research and arguing until he got his way were what he did best - and was well on his way to becoming the youngest ADA in Beacon County's history and Derek had been trying to get his business with Allison and Scott off the ground.

The business venture had been a surprise to all, especially considering the parties previous animosity. But apparently when Allison wasn't hunting the supernatural and running around with Wolves, she had an aptitude for architecture and design and it turned out that Scott and Derek worked incredibly well in construction together when they weren't ripping each other's throats out. This work dynamic had debuted when the pack refurbished the old Hale house in the summer after the Beta's and Stiles and Allison graduated. Under Scott, Allison and Derek's watchful eye, they constructed a new age home with subtle nods to Derek's upbringing, putting them on the interior design map.

Six months ago when Allison and Scott brought their little bundle of joy into the world, the first for the Hale pack, Stiles had caught Derek's eyes and had known they'd been ready. Now it seemed as though Derek had caught on as well.

Stiles moved from where he sat, not stopping until he was straddling his husband, their eyes locking together.

"Are you saying- I mean do you think- What are you-"

"I'm saying," Derek interrupted Stiles' babbling gently. "That I want to have a baby with you and add to our family."

Derek refused to refer to it as 'starting their family because as he saw it, Stiles was his family.

Stiles' lips met Derek's in a mad clash of teeth and tongue, hands instantly flying to his hair to pull him closer. Derek's own hands gripped his hips and yanked his husband closer, erasing the space between them.

"Is that a yes?" Derek murmured, detaching their lips long enough to ask the question.

Stiles nodded frantically. "Yes, yes, a thousand times yes," he said before leaning forward to kiss Derek again.

The kiss quickly turned from celebratory to filthy instantly, teeth tugging at each other's lower lips, tongues tangling together to explore mouths. Stiles' arms slid further around Derek's neck to press himself closer while Derek's hands slid down Stiles' back to cup his ass.

Stiles grinned into Derek's mouth and pulled away. He would have cursed his need for air if he could manage a word. As it was he sat there sucking in deep lungfuls of air while Derek's shifted to mouth at the long pale line of Stiles' throat.

"Mr Hale-Stilinski," Stiles murmured when he was finally able. "Are you trying to debauch me?"

"Definitely," Derek said back before nipping lightly at the hollow of his throat, eliciting a breathy gasp from his husband.

Once Derek was satisfied with the state of Stiles neck, he drew away and reattached their lips together. Their tongue tangled back together in a fight for dominance while their hips lazily rolled together in a slow filthy grind.

Eventually they had to break apart once more, both out of a need for air and out of the increasing need for something more. They breathed harshly into each others mouths, still connected by their foreheads.

Stiles eyes lifted to meet Derek's. "So let's go make a baby."

Derek's answering grin made Stiles' heart skip a beat - although he would deny it if anyone ever asked - and for a moment all they could do was smile stupidly at each other. But of course that moment was ruined when Derek abruptly stood from the lounge, almost tipping Stiles from his lap; it was only Stiles' koala-like grip around his neck and Derek's strong grip on his thighs that prevented it.

Derek hurried toward the staircase while Stiles sucked lazily at his neck and tried not to get sick by going up a spiral staircase backwards. Instead he surveyed the parts of the first floor he could see as they ascended, already thinking about baby proofing the house. The renovated Hale house had a distinct loft-like feel to it with its neck-craningly high ceilings, open spaces, floor to ceiling windows and hardwood floors, all of which disappeared from view as they reached the second floor which was full of bedrooms that the pack used to inhabit. Now however, they had all moved out, leaving the floor empty and rarely used. Derek bypassed the floor quickly, mounting the last staircase where their bedroom was.

Derek stumbled over to the bed, and threw Stiles unceremoniously onto it. Stiles waited until he stopped bouncing to shoot his husband a glare.

"Where did the romance in my life go?" Stiles asked rhetorically in his best woe-is-me voice.

"It's the secret of marriage that they don't tell you before you're actually married, babe; once you pass that whole newly-wed period, romance goes out the window," Derek said with a grin as he shucked off his shirt and tossed it somewhere behind him.

Stiles' glare intensified. "You better be joking, mister. I am expecting buckets of romance come our anniversary. There will be roses and chocolate and vomit-inducing romance. I should feel-"

Derek apparently wasn't interested in how Stiles was expecting to feel because he leaned over Stiles and pressed their lips together again, cutting off whatever he was going to say. They kissed like it would be their last - a common feeling between them what with the danger that was a constant in their lives - Derek leaning over Stiles with his hands by his head until Stiles hooked his fingers in Derek's belt loops and hauled him closer, aligning their bodies from chest to feet.

Derek's mouth tracked over Stiles throat, past the darkening bruises and sucked at the newly exposed skin of Stiles' chest as he peeled off his shirt. His breath ghosted over Stiles' nipple, prompting him to fist a hand in Derek's short hair and attempt to tug him closer. Not that it worked. Derek was determined to take it slow tonight, not just rush through a quick fuck in order to knock up his husband.

Derek grinned devilishly into Stiles porcelain skin and traced a tongue over Stiles' lightly defined abs, born from years of fighting with werewolves, drawing out a low moan from above. Derek's grin only widened in response and he glanced up through his lashes as he scraped his teeth over Stiles' hipbone, knowing it was the other man's weakness. Stiles threw his head back against the pillow as a shudder ripped through his body and he chose to look up at the boring white ceiling instead of into Derek's intense green eyes.

Which was probably for the best because the best thing he knew, his half-hard dick was being enveloped by the wet, heat of Derek's mouth. And Stiles had to blink sluggishly up at the ceiling because when the hell had Derek taken off his jeans? It didn't take more than a talented twirl of his tongue to prompt Stiles' into complete hardness and only a few well-placed sucks and Stiles was thrusting shallowly into Derek's willing mouth.

Derek was gently pulling Stiles closer and closer to the edge as he took the entirety of Stiles length into his mouth, not stopping until his nose was brushing the curls at the base of Stiles cock. After that all it took was Derek hollowing his cheeks and glancing up at his husband through his lashes in his best seductive look and Stiles was right there, on the EDGE and Stiles was begging in a low hoarse voice.

"Please, Derek. Fuck, right there. I'm so close, so close."

And that was when Derek decided to pull over with nothing more than a chaste tip to the shiny head of his cock, licking up a stray bead of precome.

"You… You- I can't believe you did that," Stiles said after a full minute of gaping up at his husband before reaching down to get a hand around his aching cock. He barely got a few tugs out, using streaks of pre-come as lube before Derek was tugging his wrist away and pinning it along with it's pair above his head.

"Not so fast," Derek murmured. Stiles was so preoccupied with Derek's hoarse voice that the actual words didn't register but he caught the predatory grin that accompanied. It was the same grin that sometimes danced across Derek's lips when he spotted his prey while hunting. And that thought really shouldn't turn him on as much as it did.

"I'm going to take this slow," Derek promised huskily, speaking directly into Stiles ear and ignoring Stiles halfhearted groan in response. "I'm going to take you apart piece by piece, until you're begging. And then, I'm going to ruin you," Derek finished and placed a surprisingly gentle kiss in the hollow beneath Stiles' ear. Derek felt the bones of Stiles' wrists shift beneath his fingers and struggled not to smile. Despite becoming stronger than the average human because of his years running around with werewolves, Stiles still had nothing on him. Or indeed any of the wolves. So any attempts were fruitless; not that that would keep Stiles from trying anyway.

Transferring both slim wrists to one hand, Derek reached down with his other hand to circle one pink nipple, nudging the bud into hardness. Stiles' nipples would be one of Derek's favourite parts of his bodies, if he were pressed to choose. They were surprisingly perky, often visible through his t-shirts and making Derek's mouth water with the need to taste them at the worst possible times.

He told Stiles in achingly perfect details how much he loved his nipples and just what he wanted to do to them while Stiles writhed under his grip, alternating between rolling his nipple between his forefinger and thumb and pinching it tightly, keeping it just on the pleasurable side of pain, knowing just how much pressure Stiles' fragile human body could take.

"I love seeing you like this," Derek murmured, the breath of his words ghosting over Stiles' earlobe, which he took between his teeth directly after, tugging just slightly. Stiles squirmed in his hold but remained silent, captivated by the low timbre of Derek's voice.

"All flushed and wanting. Nipples so hard for me," he punctuated his speech with an abrupt twist of his fingers and Stiles' back arched obscenely, pressing his chest further into Derek's touch.

"And the best part is, I know that this is nothing. Nothing, until I get my mouth on you," Derek trailed off suggestively and with one final devilish smile, ducked his head to suck one perfect nipple into his mouth, laving it with his tongue before finally biting down gently with his blunt human teeth.

Stiles yelled at the feeling, the sound almost a howl and Derek found himself idly thanking god that the rest of the pack had found their own places. It wasn't that he didn't love his pack. Quite the opposite in fact but he couldn't deny that he loved how vocal Stiles could get in bed now that they were all gone. Modern-day soundproofing could only do so much for a pack of werewolves, after all.

While Stiles was distracted by the tortuous bite and twist being inflicted on his nipples, Derek hesitantly let go of the wrists he had still had pinned to the mattress above his head. Pleased when Stiles left his hands clutched around the pillow he dragged his now free hand down Stiles torso in a nonsensical rhythm, making it impossible for Stiles to predict his next move.

Derek smirked when he saw Stiles bite his lip, struggling to choose between arching into Derek's mouth or follow the hand that was teasingly tracing the 'v' of his hips. Derek, finally tiring of the fleeting touches, sped up, skipped over Stiles' throbbing cock entirely - and ignoring Stiles' disappointed groan as he did so - and reached down to press a single dry fingertip to the pucker of Stiles' hole.

"Fuck, Derek," Stiles yelled, throwing his head back, exposing the long column of his throat as he did and if Derek's mouth was otherwise occupied sucking a hickey into Stiles' chest he might of considered adding to the collection of darkening bruises currently marking the pale flesh. The yell transformed into a high keening sound as Derek slowly pushed the single digit in up to the first knuckle before stopping.

Between the double stimulation of Derek's mouth alternatively sucking at his nipples and the gentle penetration, Derek knew his husband had to be close to coming completely untouched by now; and he didn't want him coming until he could get his lips around him again.

So he drew away tenderly watching Stiles' nipples crinkle in the cool air and answering Stiles whine as he clenched around nothing with a gentle kiss to the corner of his mouth, waiting for his breathing and heartbeat to settle down to normal, running a gentle hand up and down his thigh.

"You're-" Stiles slurred, before stopping, as though he needed to collect his thoughts. He blinked sluggishly up at the ceiling fan, which was rotating slowly, as if it held all the secrets of the universe. "You can be a real..." Stiles stopped again to swallow thickly. "...a real bastard, you know that?"

Derek grinned fondly. "Yeah, but you love me anyway."

Stiles hummed back an absent assent, looking as though he wasn't exactly sure why he did at this point.

Derek waited until Stiles' heartbeat had finally stopped racing and skipping every other beat before finally ducking his head to trace his tongue along Stiles abdomen, dip into his bellybutton, mouth along his happy trail before finally enveloping the head of Stiles cock once more. Stiles made a startled noise above him which quickly morphed into an appreciative groan when Derek hollowed his cheeks, sucking at his shaft fervently, which had not grown any less hard while Stiles had gotten his breath back.

Derek used Stiles distraction to his advantage - allowing Stiles to thread his long fingers through his hair and angle him as he wished - and slicked up a free hand with the lube he had stashed on the floor by the bed. And then waiting patiently until Stiles threw his head back in pleasure when Derek scraped his teeth just right, he slipped a finger between Stiles cheeks to toy with his rim for a second before pressing the single digit all the way inside.

Derek had to reach down to palm himself roughly then because he was risking blowing his load in boxers like a teenager at the sound Stiles had made. A high whine, accompanied by a jerk of his hips that Derek knew meant Stiles was torn between fucking himself down of the finger or thrusting up into the all consuming heat of his mouth which was still playing lazily with the head of his cock, lapping up the beads of pre-come.

Derek's erection up until that point had been easy to ignore, intent on wringing out wave after wave of pleasure as he was but now with it throbbing with need, it was hard to ignore so he allowed himself a few generous strokes.

"Derek," Stiles whimpered breathlessly, writhing down on the stagnant finger still buried deep inside him. Derek took pity on him and started to fuck him slowly, adding a second finger to join the first after a few even strokes. Derek ran a tongue down the complete length of Stiles' cock before pulling off completely and leaning back to concentrate on fucking Stiles thoroughly with his fingers, fingertips brushing against his prostate on every other thrust.

When Stiles hips were jerking slightly in order to fuck himself on Derek's fingers deeper, Derek knew he was ready and slipped a third finger in, slowing slightly at Stiles's low whine, the burn inching towards unpleasant now. With their busy work schedules it had been several days since they had last done this, so Stiles was almost virginal tight again. His muscles were clenching down on Derek's fingers like a vice and the werewolf had to take a few steady breaths in order to control himself.

To take his mind off how amazing Stiles tight, wet, heat would feel on Derek's aching erection, he turned his attention to the sprawled figure of his husband, taking in his blissed out appearance. Hands, either his own or Stiles' had mussed the slighter man's hair so it look thoroughly debauched, matching his swollen lips, bitten red by both men's teeth. The plump lips were stretched into an 'o' allowing subconscious moans and curses to escape frequently. There was a light flush staining his pale cheeks which continued down his throat and down onto his chest, colouring the porcelain flesh a pale pink. The muscles in his arms were taught all the way down to the fingertips which were clenched in the bed-sheets to maintain some semblance of control.

"Derek please," Stiles moaned. "Please. I'm so- so close," he begged, hips jerking to meet Derek's fingers. Derek took pity on his husband and leaned back down to take Stiles back into his mouth. It didn't take more than a few well timed sucks and the insistent press of his fingers against his prostate and Stiles was coming in thick spurts down Derek's eager throat. Derek swallowed around him until he was finished and continue to mouth at his softening cock until Stiles was whimpering at the over-stimulation. He drew away to thump down on the bed next to him, taking his fingers with him causing Stiles to whine at the loss.

There was a long silence broken only by Stiles' laboured breathing as he fought to come down from his high while Derek tried to think of anything but coming.

"You are seriously too good at that," Stiles murmured finally, putting way too much energy into making sure his voice didn't slur.

Derek managed a cocky grin which morphed into a barely concealed moan when he saw Stiles' eyes flicker to gaze at his aching cock against his stomach, even the burning intensity of the gaze turning him on further. There was no containing his yell of relief however when Stiles wrapped a long-fingered lubed hand around his shaft, stroking with quick, sure movements, just how Derek liked it, wrist twisting on the downstroke and thumb swiping over the leaking head sporadically.

"As good as you are at this - fuck - this is not conducive to knocking you up," Derek reminded him through clenched teeth, gums stinging as his fangs threatened to appear. But his body was betraying him, hips thrusting up into the tight circle of Stiles' hand.

Stiles grinned at him but let go, pulling instead at his hips until Derek rolled over to pin him to the bed with his weight.

"Come on then," Stiles murmured directly into his ear, hot breath washing over Derek's skin. "Get me all swollen with your pups, Der," he said, baiting the wolf side of his husband. He had been around Derek - and other werewolves - long enough to know that words like that would have no impact to the human side of them but in times of great stress or intimacy when the wolf was close to the surface? The words would more often than not have the desired effect.

Derek growled and slid into Stiles in one long thrust. Stiles smirked to himself and tried not to think about how pissed Derek would be in the morning for using his wolf against him. Derek thrust long and deep nailing Stiles' prostate on every stroke. Stiles moans grew louder and louder as he got closer and closer to his release and they were both wound so tight that he knew neither would last too much longer.

Stiles looped his long legs around Derek's waist, heels digging in to urge him faster, deeper. Heat coiled deep in the pit of Stiles' stomach and despite having just come, Stiles' unusually short refractory period - of which he was insanely proud of - meant he was beginning to harden again, coaxed on by the stimulation to his prostate.

"Please baby, please," Stiles begged, panting harshly into Derek's sweat slick skin. "Right there."

Derek growled back, the noise possibly resembling Stiles' name and thrust his hips fractionally faster.

It was the feel of Derek's knot starting to catch at his rim that got Stiles; he went from bordering on hard to needing to come desperately in just a few quick thrusts. And then Derek got a hand around him and he was coming with a wordless shout.

The feeling of Stiles clenching down around him like a vice, coupled with the intoxicating scent of Stiles, his husband, his mate completely took over. Derek thrusted once, twice, three times and came with a yell of Stiles' name, slamming into him one final time, knot locking them together.

It took a long time before either of them could do much more than blink sluggishly at each other and trade gentle kisses. But once he finally could speak, the first thing Stiles said was "get off, can't breathe," accompanied by a not-so gentle slap to the back.

"And you were complaining about the romance being dead," Derek grouched but rolled over from where he had been sprawled over Stiles, hips still stuck together. He settled into his back, Stiles' thinner frame now on top of his, smirking slightly when Stiles mewled at the consequent tug at his rim.

"Sadist," Stiles muttered, grinding down in revenge, prompting moans from both of them as it provoked a fresh wave of come from Derek.

Stiles settled back down, chin resting on Derek's chest, hands exploring the angles of Derek's face lightly, accepting the lazy retaliatory nips to his fingertips when he got too close to Derek's lips without comment.

"We could be making a baby right now," Stiles murmured, nuzzling his face into the crook of Derek's neck.

"I doubt it works that fast," Derek mumbled back, lips dragging across the warm skin of Stiles' temple.

"Of course it doesn't," Stiles grumbled. "I aced biology you know."

"The only person I know who topped their year in biology by handing in a comparative paper on Shakespeare and Robert Browning."

"That's talent right there," Stiles slurred sleepily, burrowing further into Derek's warmth.

Derek pressed his lips closer in an effort to suppress the fond smile threatening to break across his face and held Stiles close with one hand while the other reached blindly for the blanket tangled around their feet.

"I can't believe you can sleep like this," he mumbled as he dragged the comforter up over Stiles back.

"'It's a gift."

It wasn't that being knotted together was uncomfortable, far from it actually but there was something about it that kept Derek up for the half-an-hour until his knot went down. Stiles on the other hand was lucky to make it ten minutes.

Derek settled back against the pillows, reached over to switch off the soft light of the bedside table lamp and trailed a hand up and down Stiles' back rhythmically, lulled by his soft, even breathing, content to lie and think about the pup who was potentially growing inside Stiles.