MADISON, Wis. (AP) -- Gov. Jim Doyle has declared June "Fathers Make a Difference Month."

Doyle's office says one in every four children in Wisconsin grows up in a single-parent household and 21 percent of children are raised by single mothers.

Doyle says fathers are especially important to children under 3. Those kids learn and develop primarily through play and fathers spend more time engaging their children in play than any other adults in a child's life.

Sunday marks the 100-year anniversary of Father's Day in America.