Instincts and Heredity

By: Niiro Yuuyake

Disclaimer: Niiro Y doesn't own DBZ nor any of its characters. I'm just a Yaoi fangirl writing some perverted smut with the hottie Saiyajins.

Warnings: Yaoi, Minor, TrGt (yep, Goten's uke!), Shounen-ai, Lemon, Possible Mpreg, Animalistic tendencies, Language, etc.

Summary: When Goten goes into heat, Trunks' rut cycle is triggered. Now, the young Son has to deal with an over possessive, over aggressive boyfriend while trying not to get knocked up!

A.N.- Hey everyone! I want to let everyone know some things before you start reading. Firstly this is my first DBZ fic. I write yaoi like it's my life, so it's not my first time writing yaoi. In fact, I ONLY write yaoi, yep, I'm a fangirl. On the second important note, I've read many "heat" fics for DBZ, all were pretty good. But I've also read yaoi fics where "heat" was referred to as "rut" for the males(mainly canine demons). So, I decided, since Goten will be the uke, he'll go into heat and Trunks, as seme, will go into rut. I know that it's a typical, overused idea, but so what. Enjoy!

WANTED: I would like a beta-reader for this story. I have one (now) for my others, but she isn't a DBZ fan and doesn't want to beta this. So if anyone's willing, just e-mail me or let me know in a review.


Goten couldn't shake the feeling that something was very wrong. It could have been because several small animals had followed him outside early this morning or it could be because his dad and brother were staring at him as though he had a second head.

Currently, the three of them were on their way to the Briefs' home and somehow, along the way, he had ended up several feet ahead of Goku and Gohan.

Still, he could clearly feel their penetrating gazes piercing into his back as he flew.

Maybe there was a giant spider hanging on him and they were too freaked out to say anything?

They reached Capsule Corp. in record time. With Goten leading, uncomfortably; he flew pretty fast--trying to get away from their stares--but they only flew faster to keep up. Behind him, they had been oddly silent. Goku made no dumb remarks and Gohan didn't bother mentioning anything about work or his family . . . it was eerily silent.

When they landed on the lawn, Trunks was coming from the back of the building. He smiled brightly upon spotting the trio, "Hey guys!"

He watched as Goten landed just in front of him but Gohan and Goku landed a few feet away. The latter two rushed toward the front door, nearly tripping over each other as they ran into the Briefs' home

Goten laughed then turned to face the lavender haired teen again, smiling.

"Chibi, what's with them?" Trunks asked. He and Goten had been dating for a little over three months now.

Goten shrugged, "Dunno." He shifted for a second before turning so his back was facing Trunks, "Hey, is there anything on me?" He asked, looking over his shoulder, "Dad and Gohan have been staring at me weird all morning like a giant bug was on me or something!"

Trunks shrugged, "Gohan's always weird." He laughed a bit, "Forget about it, let's just go inside. I'm in dire need of a shower."

Goten chuckled as he opened the door, "But that doesn't explain dad's behavior . . . "

Trunks laughed again, but stop mid-sound, as he froze in the doorway. His sensitive Saiyan sense of smell caused his nose to twitch. A very strong, pine scent filled his nostrils as he sniffed the air wildly before turning his blue eyes upon the youngest of the Son household.

Goten had stopped talking and turned to face his best friend, "Hey, you OK? Trunks . . . ?"

But before he knew what was happening, he was tackled to the floor by a blue and lavender blur!

"Wha-!?" He fell on his back, shocked, "Trunks!? What the hell!?"

But before he could push the taller male off, Trunks was straddling him and pinning his shoulders to the ground.

Goten held in a whimper as the lavender haired teen growled. Yes, Trunks was growling at him!

"Trunks, get off!" He struggled momentarily before he was forced immobile by the taller teen.

Trunks had his shoulders held tightly to the floor, while he sat on his waist. With his knees bent, his feet locked over the younger demi-Saiyan's knees.

The lavender-haired Saiyan growled again, baring fangs Goten didn't notice he had.

"Come on, Trunks, what're you doing?" He asked nervously. Not many people stared at him as though he was a piece of beef very often.

Again, he was answered with a feral growl and nearly choked on his fear as the larger Saiyan lunged down at him.

Even though he couldn't really go anywhere, Goten tried to dodge the older male's attack. He wasn't sure what Trunks thought he was doing, but to Goten, it felt an awful lot like Trunks was . . . sniffing him . . . not attacking.

"Man, Chibi . . . you smell . . . really good . . . " Trunks' voice came out as a purr, Goten never heard him sound so . . . sexy.

Goten froze, "What?"

He could feel Trunks' head move as the other male nodded, "Really . . . good . . . "

Goten gasped when he felt something cold and wet touch his neck, Trunks was licking him!

"Trunks! Bulma says--" Gohan's voice stopped mid sentence as he stared at the sight before.

On top of his younger brother, was Trunks! Doing very naughty, intimate things . . .

"Urm . . . " Gohan was speechless. He turned to look over his shoulder as Bulma approached.

"What . . . what're they doing!?" She cried.

Gohan shrugged, "Well . . . I learned in Health class, some years ago, that when two people love each other, they--"

"I know what they're doing!" Bulma yelled, "But why!?"

Goten finally noticed they weren't alone anymore, and blushed as he said, "Could . . . could you guys . . . help?"

Gohan blushed a little also, "Do you really need our help . . . ?"

"Yes!" Cried Goten, "He's licking me!"

Bulma giggled, "Maybe you taste good . . . "

Gohan chuckled nervously, "You do kinda smell good . . . "

Goten gaped at his brother, then glared, "This isn't some joke, guys!"

Gohan blushed again, "I wasn't kidding, Goten." He looked away, uncomfortably, "That's why dad and I were acting weird . . . "

Goten's shocked expression was wiped away by a pained look. He gasped loudly and reached up to clench Trunks' forearms. "He's biting me!" he yelled, "Get him off, he's trying to eat me!"

Gohan decided to finally step forward and help. He knew his mother would kill him if he sat idly by and watched Trunks eat Goten.

He took a few steps toward the entangled duo on the floor, only to stop mid step. His shocked expression didn't fade as Trunks sat up, and with a glare on his face that would match his father's, growled fiercely at Gohan.

"Mine!" Hissed the lavender haired demi Saiyan.

Goten froze, as did Bulma and Gohan. Taking cautious steps back, the older Son stopped when he was beside Bulma.

"What's gotten into him . . . ?" He asked, confused.

Bulma sighed, knowing this all too well. "Saiyan blood is what got into him . . . " She dead panned. "VEGETA!"


He glared at the demi-Saiyan standing in front of him.

"Well?" He asked, "Don't just stand there, boy."

Trunks blushed and shifted uncomfortably, "I . . . kinda . . . sorta . . . attacked Goten." He mumbled.

His father's smirk would have been an honor, but instead Trunks only felt more ashamed. He blushed even more as Vegeta chuckled.

"So you finally showed that little runt of Kakarot's his place, huh?" Vegeta stood from the couch, his proud stance never faltering, "I knew one day you would."

Trunks frowned, "I didn't try to, " He gulped, shifting a bit when Vegeta came to stand in front of him, "Before I knew what was happening, I bit him."

His father's smirk fell a bit, " . . . Bit him?" He repeated, "How in the hell did you manage to bite him!?"

Trunks shrugged, "I don't know! One minute we were coming inside the house, the next, I have him straddled on the floor, biting his neck!" He waved his arms around in a slightly panicked fashion, "He just smelled . . . too good!"

Vegeta gaped at his son, before closing his mouth calmly, "Smelled good?" He 'hn'ed as though he suddenly understood, "I see now. You didn't attack him as I anticipated. You marked him as a potential mate . . . "

Trunks stared at his father, confused, "No, I didn't pee on him, " he said. Of course 'marking' would make him think of a lion marking it's territory, "I bit him, " he clarified, "on his neck."

Vegeta narrowed his eyes as Trunks pointed to his neck. Idiots. He blamed the boy's human side for his density, "I know what marking is, boy. What you did to that runt is the same."

Trunks stared at the man, frowning, "So . . . what now? I mean, does that mark, like, change anything, dad?"

Vegeta nodded solemnly, "It changes a lot." He murmured thoughtfully. It never occurred to him that Trunks, because he was a demi, would still go through Saiyan changes. He nodded to himself before sitting back on the couch, motioning for the lavender haired teen to do the same.

"You see, boy . . . " He said, turning so he faced his son, "There comes a time in a Saiyan's life when-"

Trunks blushed, interrupting his father, "Dad! Please don't have a sex talk with me, please! I know that stuff already." He was 17, he was no blushing virgin! Sure, he and Goten didn't get very far, but he wasn't new to sex!

Vegeta waved off his comment, glaring. "Don't interrupt me again." He ran a hand over his face, tiredly as he continued, "Saiyans are not humans. Puberty humans go through is not the same as a Saiyan's maturity to adulthood." He focused his black eyes on Trunks' blue ones as he said, "Because you are a demi Saiyan, I figured you wouldn't have to deal with the things full-blooded Saiyans would. I was wrong, " he admitted.

Trunks blushed as he frowned again, "So, what, I'm becoming an adult Saiyan or something?"

Vegeta nodded, "A bit late, but yes." He stood up, "You are at the beginning of your Saiyan life now. From here, you'll take a mate, have some cubs, and do whatever is it that you're going to do."

Trunks nodded, "But . . . you're much older than me, why don't you have a Saiyan mate?"

Vegeta grunted, "I am a prince. My father was the king. If I had mated, I would be considered a dominant male adult and ready to take the throne." He didn't feel the need to say that he, like Goten, went into heat rather than rut like dominant males were supposed to.

"Oh," Said Trunks, "So I'm gonna mate with Goten?"

"Looks like." Muttered Vegeta.

On the inside, Trunks was screaming with joy! "So that's why he smelt so good? Because he was calling out to me?"

Vegeta's brows furrowed, "What?" He shook his head, "No, I didn't say anything like that. The runt's heat seems to have triggered your rut, that's why you marked him, because he was in heat. If you weren't around, well, Kakarot or his eldest spawn would have marked the young one. It's all about instinct . . . "

Trunks blanched, "But . . . but they're related! That would be incest!"

Vegeta snorted, "And your point is?" He sighed, "Very rarely did an immediate family member mate with someone so genetically similar, but it's happened. You'd just be stuck with daft brats." The Saiyan Prince shrugged, "But as I said, it rarely happened. Even on Vegeta-sei, there weren't many Saiyans like him. So, by law, he would be taken, at birth, and raised with a dominant, powerful male. As such, when they reach maturity, they'll have a close bond and easily mate. The result? Strong cubs."

Trunks nodded. So the honor he felt at having Goten was normal? Not many guys . . . well, Saiyans got to mate with . . . what would he call Goten, anyway? If he was the dominant one, then what? Goten's the submissive one, right?

Vegeta continued on, "He is one of the rare Saiyans, or in this case, the first demi-Saiyan, to go into heat. Most Saiyan males go into rut; the dominant ones, anyway."

Trunks stood up, also. "What are you saying? Why did Goten go into heat and not rut, then?"

"Because he's mature now, ripe for the taking," Muttered the Saiyan no Ouji. He counted off in his head how many Saiyans they knew, "There's six of us, including your sister. " He said, "For the sake of our race's survival, some males, in a male-dominated populace, are born with female reproductive organs. This way, the race will continue even without females." He idly played with his gloves as he tried to remember everything he was taught, "It's simply a matter of keeping the race alive and strong, hence why a child born as such is taken to mate with a strong male."

Trunks' blue eyes were wide as everything his father said settled in. "So, Goten is one of the males with females organs?"

Vegeta nodded, "But, as I said, they come in low quantities, "He said, thoughtfully, "Mainly only when they're raised around many males without the ability." He glanced over to his son, "which means you, Kakarot, and Kakarot's eldest son do not have the ability."

Trunks nodded, "Does Goten know?"

"Probably not," Said the prince, "You should tell him, 'cause I'm not." He walked away, heading to the kitchen for a bite.

Trunks stared off into space for a while before sighing. He didn't want to freak Goten out by telling him this . . . Maybe he could get his mom to do it. She was already with him in the lab downstairs; cleaning that bite he did, earlier. She could just ease the conversation into his abnormalities . . .

Trunks sighed again, as he followed his father into the kitchen. He could still smell the sweet lingering scent of Goten's heat. He didn't know how his dad was able to march around ignoring the smell! It was so strong and potent . . . Trunks blushed as he glanced down.

Maybe he should head to his room first . . . ? He didn't want anyone to ask why he was walking around the house with an erection.


AN- Well, there you go. My first DBZ fic. Goten's 16 and Trunks' 17. I'm going with the idea that at 16, a Saiyan goes though heat/rut and is considered an adult. Trunks is a bit late(and kinda dense) . . . Anyhow, Goten's heat brings about Trunks rut(and everyone else's). It was a quick but slow prologue, but another chapter will eventually come. I'm thinking of a little GokuVegeta(uke)? Any encouragements? Review please and thanks for reading!