"You're seriously not going to come?" Meredith asked, standing at the foot of their bed with her hands on her hips. "What the hell is wrong with you?"

"My sister's pregnant and getting married to a guy she barely knows at city hall," Derek snapped. "I don't think you should be asking what's wrong with me."

"You're unbelievable," Meredith rolled her eyes. "I can't believe that you're still mad about this."

"How can I not be mad?" Derek asked.

"What if it had been us?" Meredith asked, turning from her place in front of her dresser to stare at him. "What if I'd gotten pregnant during college and we'd had to have a shot gun wedding?"

"That's...different," Derek argued lamely.

"Really?" Meredith demanded, stepping closer to the bed as she crossed her arms over her chest. "You're going to have to point out the differences to me, because I see absolutely none."

"It's you and me."

"Okay, there's one," Meredith rolled her eyes. "And you know why you can't think of any differences, Derek? Because there are none! And I'm pretty sure if that had been us, Liz would have been there in a second."

"She barely knows him."

"No, you barely know him," Meredith rolled her eyes. "What makes you think he's so bad?"

"He got my sister pregnant."

"Are you even listening to yourself? So he got her pregnant. You go out for beers with Matt and Chris all the time, and they both got your sisters pregnant."

"After they were married," Derek protested.

"Oh my God," Meredith rolled her eyes. "I can't even believe what I'm hearing. Derek, she asked you to give her away."

"There's no aisle at the courthouse."

"That doesn't matter," Meredith rolled her eyes. "Did it ever occur to you that maybe she's absolutely terrified? You're scared about the idea of me being pregnant, at the thought that you might be a father soon. Liz knows that she's going to have a baby. Everything she's ever known has completely been turned upside down, and she isn't sure of anything anymore. And all she wanted was her big brother there to support her."

"I can't," Derek insisted, reaching for a textbook. "I have a test on Monday."

"Seriously? Seriously," Meredith grabbed the textbook out of his hands and threw it on the floor at the bottom of the bed. "Your entire family is going to be there, Derek. And it's not like none of your sisters never had sex before they were married. Caitlin's even..."

"Don't finish that sentence," Derek snapped. "She's my baby sister."

"She's eighteen," Meredith rolled her eyes. "That's how old I was when we were together for the first time. And don't even think about saying it's different, because it's not."

"It is," Derek insisted. "It wasn't some fling, we weren't just sleeping around. We knew we were...us."

"I didn't know that," Meredith shook her head. "It took everything I had to give that to you, Derek, and I had no idea that you were going to be the only guy I'd ever be with, or that I'd marry you. It was all I could do to trust you."

"That's not what this is about," Derek groaned. "I just...I can't go."

"Why not?" Meredith asked, her voice softening as she sat down on the edge of the bed, running a hand through his messy hair.

"Because Dad would have wanted me to protect her," Derek whispered. "He would have wanted me to stop this. And I can't...I can't support something that I know he would have been angry about."

Meredith smiled softly as she moved closer to him, resting her head on his chest. "You're right," she said softly, reaching out to play with his fingers, smiling as his wedding ring shone in the light. "He would have been angry. But he still would have gone to her wedding."

Derek sighed against her hair. "I let him down," he whispered.

Meredith was silent for a moment, allowing him to think by himself for a moment before she giggled softly. "You know, the last time I talked to him," she said. "He was ranting about Kathleen and Chris, and how he wasn't ready to be a grandpa. Kath wasn't even pregnant yet, but they were engaged, so I guess it was on his mind. But he said that if any of his girls were pregnant before they were married, he'd make sure to give the guy a big long talk about safe sex and the importance of abstinence. I asked him if he would do that to you if I ever got pregnant and he said he would make yours twice as long."

Derek winced. "I think one of those talks was enough to last me a lifetime," he said.

"But you know what else he said?" Meredith asked.

"Hmm?"

"He said that after the whole never have sex with my daughter again speech...he would have supported them. Derek, that's your sister. And your niece or nephew."

"Nephew," Derek sighed. "I still have hope for the coming generation."

"Well, Shawn does have two brothers."

"I'm liking him better already?"

Meredith smiled as she leaned up to kiss him before she glanced at the clock. "If you hurry we'll make it," she said. "And just think about how much fun it will be to give your little sister a safe sex talk."

"I'm going to pretend you didn't say that. You can drive," Derek said. "I'll do my hair in the car."

"I don't think the car ride is long enough," Meredith giggled as she watched him pull a pair of dress pants on then slide a button down over his shoulders.

"Shut up," Derek rolled his eyes.

Meredith giggled as she reached for the heels lying on her side of the bed. "I'm glad you came around," she said softly.

"Thanks for helping me see what I should have before," Derek sighed. "I don't know what I'd do without you."

"Good thing you'll never have to know," Meredith giggled, pressing her lips to his before grabbing his hand. "Come on!"

XXXXX

"Mom!" Meredith shouted as she dragged Derek into the courthouse. "We're here! We didn't miss anything did we?"

"Derek!" Emma said with wide eyes. "I'm so glad that you decided to come."

"Yeah, I had some sense talked into me," Derek smiled, letting go of Meredith's hand to wrap around her waist. "Where's Liz?"

"She's in the restroom," Emma said. "I was sent to track down some ginger ale for her stomach."

"Is she okay?" Meredith frowned.

"Just nervous," Emma smiled.

"I'll go make sure she's okay," Meredith smiled, turning to kiss Derek quickly. "I'll be back soon."

"Thanks Mer," Derek whispered as she followed Emma towards the restrooms. He glanced around the lobby for a moment, his eyes landing on his future brother in law as he paced the few chairs that lined the wall next to the door. With a deep breath, he moved closer to him and asked, "You need someone to rant to?"

Shawn's head snapped up to look at Derek, his eyes wide. "Derek," he said. "I um... look, Liz said you weren't happy about this, and I understand why that is. Especially when you're taking on the role of her dad. But you should know that I love Liz. More than anything in the world. And we made a mistake, with this whole baby thing, but that was always the plan with her. Since I met her, I've wanted to marry her and have kids with her."

Derek sighed as he sat down, gesturing for Shawn to do so as well. "I owe you an apology," he said softly. "I know that you love my sister. And I'm happy for you, I really am. I just hate that she's giving up so much for this. And besides the fact that thinking my little sister is old enough to be having kids, I really wasn't thinking about her happiness. Or yours. So I'm sorry."

"I didn't ask her to give up Harvard," Shawn said softly. "I told her we could figure out a way to do both. But she insisted. Said she'd go to med school when the baby's a year or two old. Apparently I'm never allowed to touch her ever again."

Derek laughed as he patted his back. "Saves me from the safe sex talk I'm obligated to give you," he said.

"Thanks for being understanding about this, Derek," Shawn sighed. "It means a lot to Liz that you're here."

"I know," Derek smiled. He looked up as an entourage of Shepherd women approached, and smiled as he stood. "Hey Liz," he said softly, reaching out to press a kiss to his sister's cheek. "You look beautiful, baby sister."

Liz looked up at him with a mixture of surprise and happiness. "Thanks Derbear," she whispered.

"Alright, I believe you're next," Emma sighed.

"The judge is going to be totally shocked when we all try to squeeze into his chambers," Kathleen laughed.

"Well...it's not like it will take that long," Liz sighed. "Let's go."

Derek flashed Meredith a smile as he reached out to lace his fingers through hers. He was glad she'd talked him into coming, even though it was less than what his sister deserved. He knew Meredith was right, his little sister was happy and that was all that mattered.

XXXXX

"I swear to God, pregnancy is proof that men hate women," Kathleen groaned as she slowly lowered herself into her chair at the restaurant later that night where the family was quietly celebrating the newest union.

"Don't be dramatic, Kathleen," Emma rolled her eyes.

"I'm not being dramatic," Kathleen replied, turning to Chris. "You're evil."

"How am I evil?" Chris asked. "You know that little girl you love so much? You wouldn't have her if it wasn't for me."

"Yeah, well only someone completely evil would knock me up with an eight month old baby in the house," Kathleen snapped. "Evil."

"What's wrong?" Meredith giggled slightly.

"Everything," Kathleen rolled her eyes. "Kicking. Cramping. Fatigue. Swelling."

"It's really not that bad," Emma rolled her eyes. "My daughter is just a drama queen."

"Okay, I know you were pregnant like thirty years ago," Liz said.

"I am not thirty!" Kathleen interrupted.

"Whatever," Liz brushed her sister off. "But pregnancy sucks."

"And look at all the joy that came from my own pregnancies," Emma sighed.

"None of you even know what you're talking about," Nancy laughed. "I had twins. That's twice of everything."

"Okay, you can stop terrifying my wife now," Derek announced, causing a silence to fall over the table. Emma smiled discreetly at her son as they rest of the table stared at the couple for a moment.

"Are you pregnant?" Caitlin finally asked Meredith.

"No!" Meredith said quickly. "I mean...I don't think I am."

"Why do you look like you're hiding something?" Kathleen asked. "Are you trying to get pregnant?"

"Not...trying," Derek said carefully. "Just not trying not to."

"Oh my gosh," Caitlin squealed. "That's so exciting!"

"Mer, that's awesome," Liz said, leaning forward. "And don't worry, everything we just said...total lies."

"Well, not really," Kathleen interjected. "But totally worth it."

"Thanks," Meredith said softly. "But I'm not pregnant."

"You will be soon," Nancy nodded. "Shepherds are very fertile."

"Excuse me?" Meredith asked.

"Well there's five of us," Liz laughed. "Dad was one of seven. And his dad...I think ten."

Meredith's eyes widened as she turned to Derek. "We are so not having ten kids."

Derek laughed. "We're having as many as it takes to get one of each," he laughed.

"Oh no," Meredith shook her head. "Not if Shepherds are that fertile. Two. That's it."

"Two?" Derek frowned. "That's...boring."

"That's not boring, that's fair," Meredith shook her head. "We can have more than two if you figure out how to give birth."

"But...maybe you'll like being pregnant."

"Are you even listening to yourself?" Meredith asked. "That's probably the stupidest thing you've ever said."

"Two kids or two pregnancies?" Derek asked. "Cause twins run in the family..."

"Shep, you better stop now if you ever want to get laid again," Chris whispered in Derek's ear.

"You stop talking," Kathleen ordered. "And you," she turned to Meredith with a smile of approval. "Set up rules now. Otherwise he'll just keep telling you what an amazing mother you are and before you know it you'll be pregnant for two years straight."

Meredith nodded firmly, turning to Derek. "Two," she said.

Derek nodded, trying to control his laughter. "Whatever you say, Mer."