depends since there are 3 kinds of vampires. we have the Moroi, dhampir and strigoi. if your talking about moroi they are born from two moroi's getting together. for the dhampir which is half vampire half human either a dhampir man gets together with a moroi o vice versa. strigois however are made o force. they were once moroi forced o willing to turn, dhampirs bitten o humans being bitten