I really don't know why but I like to think that if Perry and Heinz got together, once the relationship is stable enough the baby fever would hit Heinz HARD.
He would first see Perry interact with Vanessa and just love how respectful he is with her, all calm and kind, invested in her life but never pushing for more than whar she is confortable sharing with him. Vanessa actually really likes him and thinks he's pretty cool.
The fact that Vanessa approves of him means the world to her dad.
He would then later see him with Candace. Perry and her are grocery shopping, just the 2 of them, and it's a complete coincidence that Doof is also at the grocery store with his daughter.
They all see each other, freeze, and Candace is the first to recover when she notices Vanessa. The girls start to chat, introducing their Dad/Uncle to each other and Candace starts to vibrate with excitment when she realises she's atually meeting her uncle' secret boyfriend ! She's the first of the family to meet him ! Take that Phineas and Ferb !
Doof is not at all prepared for her energy and her questions, her character is quite different from his daughter's and for a minute he finds himself at loss for words (not very common for him, to say the least).
Perry then starts to sign and grabs Candace's attention, giving Heinz some time to breath. He starts a conversation with Vanessa and asks Candace to translate so he doesn't have to write everything on his phone, and it works wonders to canalize the red head's focus. She offers to teach Vanessa sign language so she doesn't feel left out and the brunette actually agrees and seems pretty excited by the idea. They plan to see each other every tuesday, and during all that Heinz observes Perry.
He sees his fondness for his niece's excitment, gently rolling his eyes at her smug air when she plans to brag about being the first to meet "the infamous boyfriend", his pride when she translates everything easily and offers to teach Vanessa, his relief to see a completely positive reaction to this impromptu encounter. She matters to him and he obviously matters to her.
It's very heartwarming to watch. When Perry refocuses his attention on him, it's with a shy smile and a raised eyebrow. Ah, he got caught staring.
But the nail in the coffin happens a month later. The Flynn-Fletcher household is celebrating Lawrence birthday and they invited all their friends and family for a big barbecue party. Perry decided it was finally time for the rest of the family to meet Doof, so the scientist arrives 30min early, burdened with nerves and a potato salad.
Look, from what he knows about his boyfriend's family, he's sure everything will go well, but his experience with Family in general is ... not the best ? So he's pretty anxious.
He's greeted at the door by two very excited boys, and he can't even say a word that the red hair is already talking a mile a minute and completly overwhelming him.
-"Oh hi ! You must be Dr Doofenshmirtz ! We've heard great things about you, Uncle Perry says you're an inventor and so are we !"
The boy with the green hair nods quietly.
- "Uncle Perry asked us to come and greet you since he's busy with the grill so come on, we'll show you our latest invention, it's in the backyard !"
And there he goes, bewildered, holding the green haired boy's (Ferb, his name was Ferb) hand, his brother leading the way.
When he arrives in the backyard he is greeted by an amused Perry waving a spatula at him. The man must see how out of depth he is with the boys because he gives his nephews a quick look and a sharp whistle.
They both stop and turn around to look at their uncle. Once he's sure he has their attention Perry starts to sign.
-" Oh but Uncle Perry you said he was an inventor, we wanted to show him the idea of the day !"
-" And what is the idea of the day ?" the agent answers with a cocked eyebrow and an indulgent smile.
-" Well, I had this idea of repurposing this plan that Ferb did last week and- "
And just like that the attention wasn't on him anymore. Once again the agent had saved him from excited and unwanted attention. His wonderful hero in greasy apron.
Getting closer to them is a risk at this point but he is actually curious about the boys' invention, from what he's heard about them they are quite the young geniuses.
Slowly he approaches Perry from his other side and starts to listens to the brothers while looking at their uncle. He looks so tender. So ... domestic, like that, listening to the kids while grilling some burgers, his hair a bit wild and humming at all the right places during this impromptu tirade. Without realising, Heinz gets closer and closer to the man, like a moth attracted to a gorgeous warm flame.
He gets so close in fact that Perry simply snakes an arm around his middle, the spatula still in his right hand and his attention still on the boys.
They stay like this for a while, until the kids are done talking with them and go off to greet other children who just arrived.
He feels a press of lips on the side of his face and quickly turns his head to catch them in a long kiss. After a while they break apart and Perry looks at him with a light blush and slightly raised ayebrows.
-" Well hello to you too."
-"Hello Perry," Heinz answers with a sheepish smile "sorry I'm just, very very glad I came."
-"Oh ?" he hummed with a soft smile.
-"Yeah," the scientist tells him with a slightly devious air "you look very good in an apron."
And Perry doesn't need to know it's only partially responsible for his, um, sudden enthusiasm. For now. Maybe he will tell him later.
He really does look good in an apron anyway.
woof this took me a while 😭 I like the idea (parental perryshmirtz is like ambrosia to my brain) but not entirely satisfied with the result, it's a bit of a mess
but I have no energy or motivation left to do anything about it so that will do :D !!
english is not my first language so please be kind ✌️ (although I don't mind if you point out any mistakes !)
I hope you like it and if you need help picturing a human Perry you should definitly picture @chio-chan2 's version ;) ;) ;)