Who is Mike Dorsett from Sybil and what is their importance?

Mike Dorsett is one of Sybil's two male personalities. He took his name from Willard Dorsett, who always called Sybil "Mike" when she wore blue overalls and a red shirt. This outfit, in fact, appears to be Mike's standard. Mike identifies strongly with Grandpa Dorsett. He is described as a robust young man, who wants to find a nice woman, get married, and have children. Mike argues vehemently with Dr. Wilbur as she tries to explain that Mike exists in a female body and will never be able to produce either a penis or a child. Mike is an offshoot of the Peggys.