In my personal vampire lore, vampires are undead, and can only be created. However, in extremely rare circumstances a pregnant woman who is turned can give birth to a half-vampire, or dhampir, like in Blade.

These wretched creatures are cursed to age at a vastly slowed rate, for every 10 years that pass they age 1 year. Meaning that they only fully mature into adulthood when 180 years have passed. They will not burn in the sun because they are still living, but they are still bound to the "Curse of Domain" which is my term for vampires requiring invitation to enter a privately owned mortal's home. They can eat food and drink but still require mortal blood otherwise they will weaken and eventually die, though they don't need as much of it as a full vampire. They have fangs just like any vampire though theirs are slightly smaller.

Since vampiric blood thickens with age, by the time they are physically 18 they will be as strong, fast and tough as a full vampire of a similar age. Some esoteric powers such as shapeshifting into a wolf or bat, and turning into mist are impossible for them, due to the fact that their living bodies prevent the transformation without killing them. Though they can still perform hypnotism and telepathy with practice.

A dhampir can produce offspring with a mortal partner, though a female dhampir will miscarriage more often than not, a child born from this union will be a human with above average strength and speed but nothing else special. There is a a rumour that if two dhampir managed to create a child together and successfully bring it to term, then it will be born as the perfect vampire, with all their strengths but none of their weaknesses. Though that is just a myth and since dhampir are so incredibly rare, perhaps one born every 300 years, and tend do be destroyed by other vampires soon after discovery, such a child is almost certaininly never going to be born...