In the Disney version, there is no mention of Prince Charming having siblings, but in this one, he has a younger sister who dreams of someday taking the throne. Though she has a ton of bright ideas for how to make the kingdom a better place, she is constantly scoffed at by her father simply because she is a girl.
While Gwen does eventually take the throne, the ending itself is still sexist. It's only after Prince Charming decides he doesn't want to rule that the King changes his mind and allows Gwen to be his successor. However, when she asks if this means she'll be king, her mother quips, "Mhh, queen."