I believe it depends on which story your reading/watching, because many people have different mythes on vampires, except they all have one thing in common; they all kill humans to feed on them. I think that its almost impossible for a vampire to have a baby because, as u might have been thinking, why would a vampire marry a human? vampire with vampire, though, is a completely different story, in my eyes. I believe vampires have to marry in order to keep their race from extinction- and dont think of this the wrong way, but if vampires dont produce others, they will all die in the end- After all, vampires are obviously NOT immortal beings. (btw: hope this helped u bc it took me a while to think about it XP)
A baby vampire.
if it is changed into a vampire when a baby, then it will be a baby forever. ** POSSIBLE SPOILERS BELOW** if you mean a vampire's child, then this is explained in Breaking Dawn.
vampire: she had a vampire baby because the baby liked the blood and she dies and comes back to life as a vampire and is craving blood
No, Bella cannot have a baby when she becomes a vampire.
Bella becomes a vampire after she has had her baby.
Vampire
Yes
no, her baby, Renesmee is because she had the baby when she was still human and edward was a vampire.
no, but if she is immortal by mating with a male vampire she can have a baby
yes she has a vampire baby and the baby is going crazy so edward has to bite her neck
Vampire diet.
Not really, but it is possible... raise this vampire baby to live only on animal blood if you can.