And here Bruce thought he'd only have to worry about Dick Grayson, his eldest, showing up some day with a kid. No one was prepared when you'd come back from the city you're currently patrolling in with a newborn. The older male should have suspected as much when you'd gone MIA for nearly a year. It wasn't like you.
You had left Gotham to pursue a career of your own just as Dick had. What you hadn't been anticipating was meeting the love of your life. One thing lead to another and here you are, back in Wayne Manor, showing off your newborn. Bruce could not be any more worried. How could his kid have a kid already? He's not ready to be a grandfather! He just hopes you hadn't been patrolling and going out on missions while pregnant.
"They look, uhm.... just like you." Bruce speaks awkwardly as his eyes explore the pudgy and joyful expression on your child's face.