1)  When did Iowa start requiring Birth Records?
In 1880 legislation was passed creating the Iowa Department of Health and requiring all births, deaths, and marriages to be recorded at both the county and state levels.  However, with that being said, there are a few who did not start right away.
2)  What are the WPA records?  This was a project placed in motion by the Federal Government to get the economy moving in a positive direction. The main genealogical WPA (Work Progress Administration) projects were 
1. Burial listing in cemeteries
2. Federal and state census indexes
3. Indexes to naturalization records
4. Indexes to newspapers
5. Inventories of records found in county courthouses
6. Descriptions of manuscripts found in various libraries, private collections, and agencies
7. Place-name guides
8. Inventories of church records including the range of years and content covered by a church’s christening records, and the names of those buried in church cemeteries
9. Historical narratives of slaves
3)  What is special about the 1925 Iowa Census?  Iowa had many state census to help suppliment federal census records. All these records help give you that little extra information between federal census.  And in case of the 1885 and 1895 census, this helps fill in for the lost 1890 federal census.  However, the 1925 census is unique to all census records.  It is 3 sets of side by side pages (6 pages) for each person, so make sure you turn to view all pages.  The most interesting is the second set.  We are all familiar with the children listed under the parent.  But this set will tell the actual names of parents.  It will also give the place of birth, ages of the parents and place of marriage.  Set 3 will be interring for those to check for military service.