First off...in Buffy, vampires die in sunlight, by getting their heads chopped off, or getting staked. (A pointy wooden stick...driven into the heart).
There are many ways to hurt a vampire. First: Holy water. it burns their skin...pretty much the equivalent to sunlight, just not as extreme. Second: crosses. Hold one out, and a vampire won't be getting too close. Also can be compared to holy water or the sun.
Secondly: Vampires cannot reproduce. Sorry Edward. It is physically impossible.
Let it begin.
Twilight VERSUS Buffy Logic
T1. vampires sparkle in sunlight.
BL1. Wow...really? What is that even about? If you were REALLY a vampire you would burst into flame, and disintegrate into a pile of ashes...
Versus
?? Really? How is this even a question??
T2. Edward and Bella had a baby
BL2. Really? First of all, vamps cannot reproduce. However, there CAN be vampire children. That is simply because they became vamps when they were kids...Secondly: That is SO not possible. Edward and Bella? Vamp and Human? No. Just...no....
Buffy is the only VAMPIRE info you should trust. She is the slayer after all. And she did kill the master, several thousand demons, and vampires, and even has a Vamp boyfriend, (he has a soul, so he is not evil. That is how we know that vamps can't reproduce. If a vamp with a soul experiences even one second of pleasure, they will lose their soul and turn evil. Not pretty.)
PS. the only BELLA I care about in literature...is BELLATRIX.