As a result of the discordance, the brain will come to the conclusion that one of them is hallucinating and further conclude that the hallucination is due to poison ingestion.
The presence of a given genetic trait in only one member of a pair of identical twins (called discordance) provides a powerful window into environmental effects.
Whereas square lower jaws are often considered a positive trait in men, a wide mandible can cause significant facial discordance and/or masculinization of the female face.