On A Dark Ley Line lot trait.

Yup, it totally works. My normal human couple got a vampire child thanks to it. I'd say he was quite confused about it as a child; he had absolutely no clue why his eyes were glowing pink and why his teeth were sharper than usual; maybe he just assumed this was normal but uncommon for a human child. Maybe he didn't think about it at all, it just really concerned the adults around him instead.

Then he grew up into a teenager, and realized he had a massive thirst for blood. Also that the sun suddenly hurts a lot, and mirrors don't work for him anymore... And then he met some more experienced vampires. Suddenly it all clicked for him. He's not a human. He never was.