The Answer:

Only three of this country's 43 presidents can be considered only children.

Franklin D. Roosevelt

Gerald Ford

Bill Clinton

All three had half siblings, however. Roosevelt had a younger half brother. Ford had four half brothers and two half sisters. And Clinton has one younger half brother.

Interestingly, 11 U.S. presidents were the oldest child in their family, and six presidents were the youngest child in their family.

For more information on this question or other interesting president facts, check out these links:List of U.S. Presidents Presidential Factfile

—The Fact Monster