Richard (You're not allowed to say his name here) Grayson, Jason Todd, Tim Drake, Cassandra Cain, Damian Wayne on the main Earth, he sorta kinda adopted Duke Thomas, or at least takes care of him, so that's like 5 1/2. Previously, he had Helena Wayne on what I believe was pre-Crisis Earth Two (The justice society one) and one Earth where he had a kid with Talia Al Gul who wasn't Damian and was evil. Stephanie Brown dated Tim and was briefly Robin, so you could count her if you felt like it, and in the DCAU, Terry McGuinness is technically Batman's biological son. So, if you take the total number of kids (With Stephanie and Duke as 1/2) ever you get (roughly)nine, but as far as modern continuity (or at least reasonably modern) goes, five kids plus Duke.