uravily:

don’t ask what inspired this and don’t expect me to explain why.

• they’ve got three kids. it may or may not surprise you but shouto was the one who strongly encouraged them to have kids despite a lot of people thinking he would be apprehensive about being a father himself considering his own…situation…but if anything that emboldens him even more to have kids and raise them with love and shower them with affection and give them the life they deserve. tenya and izuku of course go along with it. izuku loves kids and tenya is excited to decorate their rooms and VERY excited at the concept of bringing his kids to meet “uncle tensei”
• two of them are adopted, the last kid was through a surrogate and is biologically tenya and izuku’s kid. kid #3 is basically tenya’s small twin except with green and red eyes (iida has red and blue heterochromia Thank You For Your Time) and no glasses
• izuku: so this heterochromia thing must run in the family haha
• shouto, completely Baffled as how 3 out of 6 people in their family all possess heterochromia by some broken bullshit universe law because this is anime and he’s gaining self awareness: …how………what??
• tenya: as ochako-kun explained to me; ‘science, like capitalism, is a sham.’
• their kids call tenya “father” because it’s the most formal sounding and he likes that name the most. also because tenya gets incredibly excited and greets every person whether it be a civilian he rescued or the cashier at the store with “hello! how are you on this lovely day! oh, wonderful and i am wonderful myself because i am a FATHER and i LOVE my beautiful children!!!”
• cashier: i asked if you wanted paper or plastic please sir
• kid #2: father please you are embarrassing me 
• izuku is “dad” because he is a Dad™
• mostly based this off his fashion sense because he’s the parent wearing cargo shorts and the same t shirt for 20 years and has a ton of pockets in his pants thats just filled with random ass shit. you need a screw driver? 20 dollars in change? an empty pack of gum? a sports pass to a water park that expired last june? a full bottle of water? you can find all this and more in izuku’s pockets 
• he has a shirt that says ‘#1 hero and dad’ that his kids got him for fathers day when they were still in preschool and he cherishes it. he’s still wearing it into their high school years even though it’s faded and the kids tell him to stop wearing it in public
• shouto is “papa” because he hates when they call him that and the kids love to bully him. he secretly loves it and his kids know that but they like to put on a show
• looking at the three of them you would assume tenya is the stern one, shouto is the one who acts strict but spoils them rotten, and izuku is the carefree relaxed parent. all assumptions above are incorrect because shouto is the most relaxed by far and nothing phases him
• shouto, walking into the kitchen on fire for the 7th time in a week and without breaking stride, wipes out the flames and says: dinner smells good what are we having tonight
• kid #3: papa where do babies come from
• shouto: ask your dad
• kid #3: he told me to ask you and then started muttering about hatching from eggs and walked away
• shouto: …fair enough
• tenya is the “strict” one who actually spoils them rotten because he caves so quickly and his stern expression is only a mask because he could never deny them anything
• any one of their kids on any and every occasion: father can i -?
• tenya, already in the car with his wallet and credit card out: of course where are we going
• that leaves izuku to be the Reasonable parent who is stern but gentle. he was the only one who grew up technically without any father (in shouto’s case, being without a father would’ve been a better alternative) or father figure for most of his life (until all might came into the picture) and he develops most of his parenting guide through experiences with his mom. he read and re-read “parenting for dummies 101″ and “how to raise good responsible kids” so many times he can recite the whole first chapter of each
• kid #1: when are we gonna see grandpa might again?
• izuku: whenever you want! we can see him at the end of the week i’m sure i can take a day off
• kid #2: what about grandpa and grandma iida?
• izuku: sure! we’ll see them too
• kid #3: what about papa’s dad?
• izuku, who already Thanos Snapped endeavor out of this universe and was a witness to the symbolic spiritual adoption of shouto into midoriya/iida/all might’s family after izuku, shouto, and tenya got married: i just said we’re gonna see grandpa might next weekend, kiddo
• their kids know how to play the Asking For Expensive Presents Game but sometimes they know they’re fighting a losing battle
• kid #2: papa can i have an xbox
• shouto: go ask your father
• kid #2: father may we buy an xbox
• tenya, knowing full well if he caves he’s going to get a very Disappointed look from izuku and max out his credit card again: …please do your chores first.
• kid #2: sweet
• tenya: and ask your dad.
• kid #2: cool
• kid #2 the moment tenya is out of earshot: shit. dad’s gonna say no. i better ask sibling #3 to pull out the puppy eyes and beg