One generation. Jesse is Dean & Mickie's son. Cain & Abel are Adam & Jackie's sons. Brooke is Harry & Maggie's daughter (you know, the ghostfacers). As for Ethan, he's Drew's son (and Castiel's ?). Drew is Sam and Dean's (adopted) sister.
Voilà, I hope it helped. Welcome in the group.
Haha, Deany ? I'm not sure Dean would like being called "Deany". Just like Sam doesn't really like being called "Sammy" by anyone except very close family lol.