I think they said that Bruce was 35 in the 1989 Movie by Tim Burton.
Batman lasted ten years before his knees gave out in the Nolan Universe.
Gotta wonder if that Engine from the last Nolan movie he built was the plan all along?
(Orphanage feeding the cave an endless supply of young boys.)
Bruce just had to be Batman long enough, but not necessarily well enough, that the orphan kids wanted to be Batman hard enough to put on the suit and run into gunfire on a nightly basis.
I can imagine them going though 9 Batmen on a bad week.
Gotham is going to run out of Orphans fast.
Oh my.
What if Bruce was making Orphans?
Intentionally impregnating women unlikely to keep his children.
Obviously Batman's children, not Bruce Wayne's babies.
But if he rescued 12 women a night for ten years and half of them were feeling thankful, or where crackwhores who were just rolling with the situation and not caring about the consequences... Batman didn't want to impregnate women who would keep their children. So his first choice would probably be mentally ill, alcoholic homless people. Anything to make sure that that orphanage was stocked wall to wall with Wayne DNA.
Of course if you put that many handsome, fit, young men together in closed quarters, who do not know that they are related, it's all going to get very eyes wide shut very quickly.