The thing is that Vlad Tepes had descendants-- his granddaughter lived in Sibui after the murder of her father, Vlad's son. So he did have children and grandchildren. There is also a connection with the British Royal Family and Queen Mary of the United Kingdom, who is a descendent of Vlad Tepes.
As for Count Dracula--- he was undead and as far as reading the book by Bram Stoker Dracula-- he did not have descendants. Although he may have had a child.