What field of work was shared by the parents of the man with the middle name Gamaliel who served as a U.S. Senator from 1915 - 1921?

The field of work shared by the parents of the man with the middle name Gamaliel, who served as a U.S. Senator from 1915 to 1921, was politics. The man in question is Warren G. Harding, whose parents were both involved in local politics in Ohio. Harding served as a Senator before becoming the 29th President of the United States.