I've made my decision. If Morgan rolls a whim to turn her son Cormac into a vampire, I'll allow it. Same if Cormac wants his mother to turn him into a vampire.
I've only had one teen vampire before, and that was Wolfgang Munch in my premades save (not the same save as Morgan being a vampire). I recently used MCCC to humanize him however. So there's always that option - or I could do what I did when I turned Morgan's husband into a vampire and do a 'save as' to have an alternate copy of the same savefile, so I could have one save where Cormac is not a vampire and the other save where he is.
