I feel like Jazz should have her own Bio-dad Aus Now Bruce is a popular choice for most bio dad AUs, but let's add some variety. Harley Quinn is another popular choice, it kinda fits since they have ties to psychology. But let me give you another choice. Harvey Dent. Let's say Maddie and Harvey met at one of Brucie Wayne's fundraiser events, they hit it off, get a bit tipsy, then boom. Jazz's born. Jazz looks so much like her mum that Maddie doesn't even think that Jazz is not Jack's kid. (She does notice some things about Jazz that she couldn't have gotten from Jack or her, but admitting that would probably ruin her marriage, so she employs blissful ignorance.) Harvey, of course has no idea Jazz exists. Years pass, truths come out (or not), tears are shed, life goes on. Now Jazz is looking at schools, and she finds a good one in Gotham, you know, the home of her bio dad. She decides to reach out to Harvey. So, she talks it over with Jack and Maddie and they agree to let her go. Now you could have Jack and Maddie know that Jazz isn't Jacks kid and approve of her reaching out to Harvey, just them being supportive. Or, you could have them not know anything, and have Jazz do this behind their backs as an attempt to have a semi decent role model in her life. Your choice. But anyway. Here Harvey is, planning something (Next court case or next crime) and then, out of nowhere, a kid shows up on his doorstep saying "Congratulations, it's a girl, where's that child support?" And he's just so confused, like how did she find him (Tucker of course) and where were her parents? Harvey who's very concerned: ehh, you do know I'm a criminal, right? Jazz: My mum and other dad have a portal to hell in the basement, trust me, you're an improvement. Harvey who's even more concerned about this kid: ??????? Or you know, Slade Wilson is also an option.