Peter EROH (b. 1867) m. Martha E. ZERFOSS

I'm looking for information/parents of Peter EROH (b. 1867 PA).He married Martha E. ZERFOSS (b. 1875 PA) before 1896.They had several children: George Daniel, Paul F., Mabel E., Iona M., Ellen L., Sarah, Ruth, Edna, Nora, Luther, Clarence, and either a Sadie M. or a Sydney.In the 1920 census "it" was listed as Sydney (male, age 21).In the 1910 census, "it" was listed as Sadie M. (female, age 11).I would also like some clarification on that issue too, if possible.