In Sharon M. Draper's Romiette and Julio, the close relationship both title characters share with their mothers is critical for both character development and theme. The two mothers, Lady Cappelle and Maria Montague, serve as role models and sources of inner strength the teens greatly need as they battle against racial prejudice in the story, and these character traits help to illustrate the theme concerning the need to fight racial prejudice.
It is extremely evident from early on in the book just how close the two teens are with their mothers. Romiette Cappelle, called Romi for short, has such great respect for her mother that she wants to emulate her. We especially see the great amount of respect she has for her mother in the diary entry she writes in the second chapter in which she relays to the reader information about herself and her parents. For example, she notes that her grandparents named her mother Lady "because that is what they expected her to grow up to be--not a woman, but a lady," and that is exactly how Romi perceives her mother as being and wants to emulate. More importantly, Romi wants to emulate Lady's independence, strength of character, and self-assertiveness--all of which are traits necessary for Romi to have as she overcomes the threat the gang called the Devildogs poses due to racial prejudice, after she starts dating Julio.
Both Romi and Julio learn perseverance, independence, and inner strength from their mothers. Without these traits, they would not have had the inner strength to continue their relationship once they were threatened by the Devildogs. What's more, once they had been kidnapped by the Devildogs and floated out in a boat in the middle of a severe storm, without any oars, Romi and Julio may not have found the strength and courage to survive the ordeal had they not learned their mothers' qualities due to their close relationships with their mothers.