A/N: It seems the only time I post fic on here it's always for another fandom. It should come as no surprise to anyone that when I decided to binge watch The OC as a way to start the new year, I fell for Sandy and Kirsten, hard and fast. It's been nearly a month, and I still haven't shut up about them. This is just a tiny, fluffy piece inspired by the Cheerios commerical that aired during the Superbowl. It's an AU set pre-series, when the Cohens lived in Berkeley the first time.

Disclaimer: I do not own a thing.

It had become a well-known fact in the Cohen household that Seth Cohen was not looking forward to becoming a big brother.

When Sandy and Kirsten had sat down with him three months ago to tell him he was going to get a little brother or sister in a few months, his immediate response had been to vehemently oppose the idea and suggest getting a puppy instead. Sandy and Kirsten had laughed, ruffled his hair, and told him he'd warm to the idea by the time his sibling arrived.

Over the months, he'd pouted, thrown tantrums, and even gone so far as to try to lock himself in his bedroom, all to no avail. Kirsten was worried, but Sandy assured her that by the time the baby was born, Seth'd be fine.

"But what if he isn't, Sandy?" Kirsten asked, looking up from the laundry she was folding, brow furrowed. She chewed her lip, blonde hair falling out of the messy ponytail she'd tugged it into earlier as she picked up the last pair of Seth's jeans from the basket. "I mean, how is he going to adjust to a whole other person in the house?"

"All kids go through this Kirsten, it's natural. You can't tell me you were 100% sold on getting a sister when you were a kid," Sandy replied, looking up from the file he was looking over. "He's still got three months to get used to it."

"Maybe we should talk to him again," Kirsten said, clearly still worried as she set the now-folded jeans back into the basket. "It's a big adjustment for a four year old."

"I think you're worrying too much, honey," Sandy said, dropping a kiss to her forehead before he helped her stand, fingers trailing lightly over the swell of her stomach before he picked up the laundry basket, deaf to her protests.

"I can still carry a laundry basket, you know," Kirsten said, trailing behind him and poking at his shoulder, rolling her eyes when he began to hum rather than answer her. At the top of the stairs, he deposited the basket in Seth's room while Kirsten checked on him, smoothing back his already-unruly black curls and pressing a kiss to his head, smiling when he mumbled slightly in his sleep and curled up further under his dinosaur comforter.

"He's gonna be fine, I'm tellin' ya," Sandy said as they got ready for bed. He watched from bed as Kirsten brushed her hair, dressed in a nightgown she'd bought recently, dark red and shiny, and capable of keeping her ever-growing bustline in check. She threw him a look over her shoulder, lips curved in a way that told him she was trying not to smile.

She crawled in next to him, lacing her fingers with his as she settled in beside him, head on his shoulder.

"Whatever you say, Sandy."

The next morning, Kirsten walked into the kitchen to find Sandy and Seth eating cheerios. She poured herself a cup of coffee and leaned back against the counter, watching as Seth played with a few fallen cheerios.

"Hey Seth, look- you've got two cheerios there, just like Mommy and Daddy," Sandy said, nodding towards his son's fingers. Seth looked down, and lit up as he dragged another one closer, forming a triangle.

"And me!" he exclaimed excitedly, causing both Sandy and Kirsten to smile.

"And in a few months, you're going to have a little sister," Sandy added, dragging another cheerio into the bunch and making a square. Seth stared hard at the square, looking up at his dad for a minute before dragging another cheerio over and placing it right next to the cheerio he'd designated as himself.

"And a puppy," he said, challenging Sandy with a look. "A boy puppy."

Sandy looked back at Seth for a moment before smiling, shaking his head slightly. "Deal."

He looked up to find Kirsten glaring at him, though the amusement shining her eyes negating the stare.

"If you think I'm looking after a newborn and an unhousetrained puppy all by myself, you've got another thing coming Sandy Cohen."