1960s: Many women in the United States begin to question their traditional roles in society as strictly wives and mothers. Women consider careers in areas previously dominated by men, such as medicine, law, and politics. The percentage of female medical school students in the United States increases from 5.8 percent in 1961 to 10.9 percent in 1971.

Today: Women make up slightly more than 45 percent of the entering class in U.S. medical schools. By 2010, the American Medical Women's Association predicts, the figure will reach at least 50 percent.

1960s: King Idris I, along with an elected parliament, rules Libya. The Libyan oil boom is beginning, and Libya encourages American and other foreign companies to enter the country to drill for oil.

Today: Libya's full name is the Great Socialist People's Libyan Arab Jamahiriya. It is ruled by Colonel Muammar al-Qaddafi, who has decreed that all businesses must be...