Justice league finds out Batman is a mother.
They don't know that he is Bruce Wayne. They don't even think that he is a human. So when they accidentally met Cassandra and Tim and are told that Bruce is their parent, their first conclusion is that, ah yes. Batman is their mother. And being the gremlin theatre kids they are at heart. Batkids feed the fuck out of this misunderstanding.
Yes he gave us birth, our species reproduce asexually . Do you know he was pregnant during that mission? That's exactly why he was so grumpy. Oh yeah cryptid pregnancy works different so he was sick and sensitive but the baby never got hurt. Shadow ale helps a lot with the cramps you see. Everyone in the family, even Alfred is aware of these lies that are being spread like butter. Everyone except, Bruce. When he decides that it's time for Damian to meet JL (He was the only member they don't know yet), Dami, in a small voice says he want to mess with the Justice league.
He. Mister "these shenanigans are an absolute waste of time and only bring shame to the mantle of Batman", wants to fuck with the league.
Grayson is weeping while cupping dam's face, Jason has a hand over his mouth clutching his gun to his chest, Tim swoons and falls in steph's arms. Cass is delighted to know that their brother has finally learned the ways of the bats. Alfred cracks his knuckles and Duke starts preparing the slide on the computer cuz Tim is still faint.
They start being very careful with B in front of the League. Let supes handle the heavy lifting, don't worry we have the strategy already prepared, B should I get you some Shadow ale? The league keep drinking up the crumbs and finally. Lantern cracks.
This is the moment they have been waiting for. They tell them nothing. Now desperate, Canary goes to Gotham for Red Hood of all people. Red hood, still on odds with the Bats, explains that B is expecting. The league is soo happy. They goes to Batman to congratulate him. Only for him to be missing. (He has been put to bed rest by Alfie cuz of an injury for 3 days).
The kids explain that he will be in labor till the child comes out. Everyone on the watchtower is so stressed that it got the family feeling a little guilty. But pranks are like that. For success forces you to do some things you are not proud of. The results are always worth it. And god was it worth it.
When B returns to the watchtower with Damian, his confusion is visible through his cowl. Because why is Supes spinning him around and Diana is...kissing his forehead? What's with all this goth decoration? Canary with tears in her eyes kneels before Damian and he lets her pick him up!? Flash interrupts the series of congratulations being shoved at Bruce with a question," Should you really be working after the labor Batsy?" And Damian backflips from the embrace of the super crowd and breaks down laughing because his father looks horrified. Suddenly all the batkids are there. With shit eating grins on their faces, rolling on the floor hysterically (they all were hiding in the tower for a long ass time).
Batman growls and demands answers while the league stares in dumb. Cass with a smile on her face looks in her dad's eyes. And Bruce, being fluent in gremlin bullshit. Understands everything. Alas the league was in need of a verbal explanation. After they reveal the truth they are completely dumbstruck in silence. then. they explode in chaos. Everyone nut Dick was too busy to notice the smile on batman's face.