At first Tony thought it was just weird timing and coincidence. He'd visited Harley and his sister, and Harley being old enough now for social media, the pictures were everywhere. The Avengers mocked and teased, but not nearly so much as Pepper so he mostly ignored them. Then Clint caught him trying his best at 'girltalk' with Peter, who apparently had no one better to ask relationship advice of. Which is just Tony's life. No biggie.
Then Clint dumped his kids at the tower during his visitation hours while he nipped out to file some papers with wifey. Or, well, soon to be ex-wifey. Sorry Clint. Guess going on the lamb and getting arrested when you said you'd retired has consequences.
Fine. Massively unexpected from Clint of all people, but they were doing better these days. It was fine. He knew the kids from their time hiding out on Clint's farm from Tony's own evil brainchild. The boy was easily entertained with Tony's game system, and the girl was more than happy to trail Tony around asking inane or bizarre questions as he soothed the baby. Whatever.
Then Sam arrived with a niece he needed Tony to keep an eye on for an hour. Then two days later Scott dropped his daughter off, looking very torn but kissing her on the forehead and promising he'd be back as soon as the work thing was done. Tony didn't even get the chance to say a word in response before he was left alone with an eleven year old he'd never met and who had a whole lot of snide comparisons to make between his suit and her dad's. The comments petered off after a trip to the workshop that Scott would probably try to kill him over. Try. Because Tony's suit was way better, obviously.
And it kept happening.
"Okay, what the hell?" Tony finally asked as the Avengers and X Men left him in charge of a recently rescued group of child mutants instead of one of the people who actually had kids.
Steve frowned at the language but didn't answer the question.
"When did I become superhero daycare?" Tony continued.
Steve's frown deepened in confusion. "What do you mean?"
Tony gestured expansively at the kids to either side of himself.
The confusion didn't clear.
"There hasn't been a full week lately where someone hasn't thrown their kid or kids at me," Tony stated. "I'm not a goddamn nanny."
"You love kids though," Sam said like it was obvious.
Tony just stared.
"Yeah, your place is the only option we have for childcare," Clint said begrudgingly. "Anywhere else and my darling daughter turns into a demon."
"You guys have been letting Tony take care of your kids?" Steve asked incredulously.
"Exactly!" Tony said, pointing at the expression on Steve's face. "I am not the kind of guy people trust with their kids. What is wrong with you all?"
Sam's brow crinkled. "You're great with kids."
"Am not!" Tony protested.
"Amy said you taught her to build an engine and then went out for ice cream," Sam said in rebuttal.
"Ice cream for dinner and hands on interaction with internal combustion are not good childcare strategies," Tony argued. "I just didn't know what to do with her."
Sam smiled a little. "Most people would've sat her down in front of some cartoons and made her a sandwich."
"Exactly!" Tony said.
"Your way is better," Sam shrugged. "She had fun with you. She's invited you to her birthday party."
Tony looked at Steve for help only to be betrayed by the amused grin Steve gave him.
"Who'd have thought? Tony Stark is great with kids," Steve teased.
"Am not," Tony repeated.
"Kinda are," Clint disagreed.
"What I miss?" Scott asked, appearing in their midst an popping back his helmet.
"Tony says he's not good with kids," Clint told him.
"What? Tony's great with kids," Scott said.
"Right?" Clint agreed.
Tony pointed at each in turn. "None of you should be allowed to have children. You have terrible judgement."
A small mutant tugged at his elbow.
"Just a minute," Tony said apologetically, fingers rubbing gently at the kid's hair. The kid crept in closer and waited with wide eyes.
"Ask him to show you the holograms," Sam suggested. "Amy loves those."
A crowd of little heads nodded.