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For as long as Peter could remember, he had always longed for a sibling. He couldn’t remember back into his early childhood days, when his parents were still alive, but May and Ben had always laughed when they’d recount the stories of the various ways he had asked them for a sibling. Peter still had the same desire for someone to grow up with when he moved in with his aunt and uncle. He could recall begging them to have a baby because a cousin was just as good as a sibling in his eyes. May and Ben had both explained to him that they had never planned on having kids of their own, but Peter still wanted a sibling so he could have someone to play with.
When Peter started school and slowly began making friends, his longing for a sibling finally began to diminish. He had finally formed a connection with other kids his age and had found others to play and spend time with. As the years passed, Peter eventually stopped bringing up a sibling altogether and no longer expressed any desire for one. He understood that May and Ben didn’t want to have another child, and he learned to respect that. All his previous feelings of desperation and loneliness were pushed to the back of his mind where they were subsequently forgotten.
Yet, all those feelings suddenly came rushing back into the forefront of his mind as Tony Stark placed a tiny baby girl, wrapped in a soft pink blanket, into his arms. As Peter stared at the small baby with the large, chubby cheeks, light brown hair that barely covered her head, and huge brown eyes that stared back at him in amazement, he couldn’t help but think that the happiness and love spreading through his chest was exactly the reaction that he would've had all those years ago if he had been given a sibling.
“She’s so tiny,” Peter uttered as he carefully brushed his thumb against the soft skin of her face. He grinned as the baby made at least what he considered an attempt at a smile as a response to his actions.
“Look, she already loves her big brother.” Pepper softly laughed as she watched Peter gingerly hold her newborn daughter in his arms and smile at her like she was the most precious thing he had ever seen in his life. The reaction was warranted. That is how both she and Tony had felt when they had gotten to see their daughter for the first time too.
“Her big brother?” Peter’s head shot up as he registered what Pepper had just said. He looked between her and Tony with a look of complete shock on his face before staring confusedly at the baby in his arms as if he was unsure how he could ever be considered a brother to the tiny infant.
“Yeah, Pete, her big brother. Pep and I consider you family. You’re basically our first kid, no matter how unofficial it may be. Well, besides the bots, of course. I can’t exclude them from the family.” Tony joked in an attempt to make Peter smile. When he still only received a confused stare in response, Pepper quickly took over the conversation.
“But as much as we like the bots, we want Morgan to grow up with an actual human sibling too.” Pepper continued as she reached out her hand to squeeze Peter’s arm. “I can’t speak for you or Tony, but I know that I was lonely growing up as an only child. This is going to be a learning experience for all of us, but Morgan would be so lucky to have you as her big brother.”
“Wow, Pepper, thank you. I...” Peter trailed off as he struggled to come up with the right words to say. He stared down at the now sleeping baby in his arms as he tried to picture himself as her brother. After another beat of silence, Tony quickly jumped back into the conversation and gave Peter a reassuring smile.
“You’re a good kid. You’re smart, and you have the biggest heart of anyone I know. We think you’re an excellent choice so, there’s a spot open in the big brother department for you, kiddo. If you want it, that is. It’s completely up to you. Don’t feel pressured. It’s totally fine if you don’t want the job. She’ll make room in her heart for you no matter what you chose to be to her.”
“No, of course, I want the job. I’d be honored to be her big brother. How could I ever refuse that offer when I have the cutest baby in the world in my arms? Thank you so much for even asking me.” Peter quickly insisted as he looked between Tony and Pepper to make sure they understood the conviction in his voice before he returned his gaze to his new little sister. “I promise I’m going to be the best big brother in the world, Morgan. Just be patient with me, okay? I’m new at this big brother thing. You know, I always wanted a little sister or brother when I was younger, and I’m so glad I finally have one. I already love you so much. I’m so honored that I’m going to get to play a big part in your life. Thank you for letting me be your big brother.”
As she heard Peter’s voice, Morgan once again opened her eyes and gave the boy a lazy smile before tightening her grip on his thumb and falling back to sleep. Peter gave her the widest smile he could muster in return.
Tony and Pepper both watched the scene with a huge smile on their faces, and tears of happiness silently streaming down their faces. They quickly caught each other’s eyes, and their smiles only grew as they returned their attention to the chair next to Pepper’s bed, which was holding both of their children. Peter eventually lifted his gaze from his little sister to once again meet their gazes and allowed them to see both the tears that were freely flowing down his face and the unshed ones which were somehow making his eyes shine even brighter with happiness.
“Well,” Tony finally said as he cleared his throat and tried to subtly wipe his face, “I’m so glad you said yes, Pete because I had already bought you both matching shirts.”
He quickly crossed the room and opened up a small closet, where he had stored all of their belongings when they had arrived. He pulled out a shopping bag and opened it as he sat on the edge of Pepper’s bed. He first pulled out a plain white shirt for Peter that had written on it in colorful bubble letters: “I’m the big brother!” He set it aside as he pulled out the tiny matching one for Morgan that read: “I’m the little sister!” in the same colorful bubble letters.
“I picked these up in the gift shop earlier. Here, put it on.” Tony grinned as he quickly traded Peter the shirt for the baby. “I need pictures. I’m going to have them framed and include them in the birth announcement.”
Peter laughed as he quickly replaced the shirt he was wearing with the new one and indulged Tony in taking as many pictures as he wanted of the pair. He only smiled wider when Tony pulled out a Spider-Man onesie midway through the impromptu photoshoot to change Morgan into.
Peter had given up on his longing for a sibling many years ago when he finally realized that it was a dream that was never going to be fulfilled. Yet, as he smiled down at the tiny baby in his arms, he was so glad that the universe had still found a way to make his childhood dream come true. He didn’t even mind the years it had taken for him to finally get a sibling. The small baby in his arms was more perfect than he’d ever thought was imaginable, and she was definitely worth the wait.