From The Grey House:
Vincent turned, going back into the house. Joseph stayed for a moment, watching the creatures of the night. A stray thought flitted through his mind, something someone told him once, right before his change. A fortune teller stated he would never be a sire to a child. He thought it an odd turn of phrase, but while human, never had children. In all his years many years as a vampire, he had never sired anyone, either.
The old vampire never met anyone he wanted to change, and now he was being asked to change Natalia. The first time he faced her, when she mentioned knowing him, dreaming of him, he walked away, knowing it was best. He had dreamt of her too. Of bringing her a goblet of blood and calling her child. It made no sense against what the fortune teller stated, but then, they didn’t really see the future. At least, the fully human ones did not.