Story 1 - The relationship between a student and his teacher Story 2 - Sperm Donor Texas Teacher: A Texas teenager, whose former teacher is serving jail time for having a sexual relationship with him, opened up for the first time about their affair and said he had suicidal thoughts after her arrest because he felt guilty. Sperm Donor: "20/20" reports the story of a woman who caught the "genealogy bug" and became obsessed with investigating her family history. What she discovered would unleash a monster from the grave, and threaten her entire family. "In an instant" Crossing the line CREDITS: 20/20 ABC