Antonietta looked at her son, astonished. She never imagined that Vittorio knew, let alone that Marco knew the truth. Confusion and surprise were evident on her face.

"How? How could you know? How could Marco know?" she asked.

Vittorio, with a subtle smile on his lips, calmly explained, "Ever heard of biology, Mama? Thanks to the excellent school I attended, there was a time when I learned about blood typing, Rh factor... During class, I questioned my teacher's approach. After ...