If there's one thing we've learned after 5+ seasons of True Blood, it's that men's buttocks are the new side-boob. But if there are two things, it's that vampires take the bonds of blood very seriously. Eric Northman believes Godric is God; his maker exercises more influence over him than the actual vampire goddess, Lilith, despite Lilith being older, taller, and far more naked. Pam's devotion to Eric is absolute, even though, like many fathers of daughters, he'd rather self-immolate than listen to her girl problems. Bill and Jessica play out like single dad and rebellious teenager, with draining humans subbed in for draining Boone's Farm on the list of infractions that merit an awkward lecture.
All of which begs the question: in this world of incest-happy TV, are hyper-sexual vampires cool with diddling their relations? You'd think that, given their callous disregard for human morality, these toothy beasts would feel no compunction about forming the beast with two backs with their vamp children, parents, and siblings. There's no biological reason against it, what with their wombs being as vestigial as our appendixes. But there do seem to be rules, or at least guidelines.
For starters, responsible male vampires do not have sex with their daughters. Even after turning into a shrieking puddle of ancient blood and nearly pulling Jessica's heart out of her chest, Bill's first instinct in the bedroom is to tuck her in and say nighty night. Of course Jessica is a child, for whom Bill bears full responsibility for making, and at least for this century that eliminates his temptation*. But what about Eric and Pam? Even when Northman went full Viking on Human Swynford De Beaufort, his interest seemed more protective than sexual. Once he turned her, it became purely paternal, and their sexual history became a wedge in the new relationship. The lesson: don't make a woman into your vampire daughter just because you slept with her, and feel that you owe her something. Do it because you see budding leadership qualities that could make her a future Magister, or even Chancellor of the Authority.
While there are plenty of powerful female vampires on the show, none of them are shown as being particularly great parents in the vein of Godric, and the Lorena-Bill storyline is just ghastly: she wanted a depraved relationship with a good man she could turn into a monster but still exercise complete control over, so she bit Bill in the neck. Maybe she turned into a hooker-eating son-molester because something horrible happened to her back in 900AD, but regardless, if you're a mom, and you're undead, raise a manpire, not a blood-drenched boy toy.
By contrast, the vampcest between Eric and his sister Nora might be tempestuous, but it's also portrayed as hot, not demented, one of the few incestuous TV relationships that hasn't come with (so far) serious repercussions. Basically, if Taboo II had had lines like "We fight like siblings, but we fuck like champions", people not named Adam Carolla would remember that they made a second Taboo**.
Championship sex aside though, Pam and Tara's relationship stands out as the one with real promise, not because the creators have a lesbian fixation, but because the two might as well not be related. Pam has no maternal instinct whatsoever, and Tara, despite her human mom ranking high on the worst person in the world list, has no desire for a substitute mother. Pam takes no responsibility for making Tara, and Tara assigns her none, leaving each of them free to get passionately aroused over the other's strata of fierce independence overlaying even fiercer emotional craving. This might really be Tru:Love.
This was far from a complete breakdown, but if you do become a vampire, hopefully it'll serve as a reminder that, even if you treat the rest of man's laws like the toilet paper you no longer have to use, you generally still shouldn't get turned on by the one who turned you, or the ones you turn.
*For Bill's crystal-clear views on human-on-human incest, consult Uncle Bartlett's Quotations.
**Actually, they made 23 of them, even though, just like the fourth Friday the 13th, the third installment was disingenuously subtitled "The Final Chapter".