1950s: The U.S. presidency term is restricted to eight years.

Today: The U.S. presidency is still restricted to eight years, but there are discussions about removing the requirement that an individual must be born a U.S. citizen in order to run for president.

1950s: It is reported that lung cancer is linked directly to smoking. However, tobacco companies continue to produce and sell cigarettes without any repercussions.

Today: Millions of people still smoke cigarettes, even though the habit has been linked directly to many diseases. However, tobacco companies are increasingly held responsible for producing and selling dangerous products to consumers.

1950s: James Watson and Francis Crick decipher the structure of DNA, opening an entirely new field of biological study: genetics.

Today: DNA is at the forefront of scientific exploration into genetic disease, stem-cell research, and cloning. Religious and scientific communities are...