Depends on what vampire lore wewe reference. The Wanyonya damu in Vampire Academy, Blade, van Helsing, and Twilight all can produce children. (NOTE: I don't mean change humans and call them children, I mean females get pregnant, carry, and birth actual vampire/half-vampire babies.)
Every vampire book, movie, t.v. show, and cultural lore is different. There is no set rule for what a vampire can and cannot do.
According to Middle- and Eastern European folklore, human and a vampire can have an offspring called dhampir. He (?) is usually especially talented vampire-hunter.
Yes. That's how zaidi and zaidi Wanyonya damu come into the world. They basically have offspring the same way humans do. It's kinda a different subject I don't wan to get into.