I don't know all the scientific theory but I do know that I have hybrid bluegill that are BG/GSF cross. Don't know which was the male. I also know that my fish were stocked 10 years ago and I have at least 4 distinct year classes in my pond. So they definitely have reproduced. It did take a few years to notice any reproduction however so I suspect very few females in the F1. As proof I have eaten close to 400 of them so far and have yet to cut open one that was obviously a female. At least I've never seen any eggs. I have eaten substantial numbers of fish from the F1 and F2 generations. Rarely kill any from the F3 and younger class. I expect to see more females as I get into the younger classes. I think this all agrees with what people are saying here.

Gotta get back to fishin!