Morgan and her twin brother Spencer was born in Mexico City. Her father had just gotten killed at the time of her birth. Her mother had been left greaving for the rest of her life, until she met Jameson Arch on vacation in Argentina. They soon got married and moved to Danville to life near Yasmyn's brother - Dr. Heinz Doofenshmirtz. Soon after moving into the purple house 3 doors away from the Flynn-Fletchers, she meets Phineas and Ferb. Before they introduced themselves, Morgan called Phineas Mr. Triangle and she called Ferb grass head.