Fred shows up in the 1910 Census married to Elvina (but Alvina shows up in an earlier census--1880 with the spelling Alvina Huse, so this is probably a misspelling by the 1910 census enumerator).
Fred's children in 1910 are listed as:
1. Hary S. Wehking (probably your Steven Harry Wehking--more spelling errors by the enumerator), 6 months old in May of 1910, which puts his birth in 1909.
2. Charles F. Wehking, age 10
3. Fred C. Wehking, age 9
4. Rose M. Wehking, age 7
Fred also shows up in 1900 Census married to
Alwina Wehking (yet another census enumerator spelling error) with just one child:
Charles F. Wehking, age 10 months.
Fred's birth is listed in this census as Aug. 1876
Alvina's birth is listed as Oct. 1878