Her television sitcom, "I Love Lucy," made U.S. cultural history in at least two ways.
1) When Lucille Ball became pregnant, she refused to conceal it, had it written into the script, and had her character, Lucy, appear onscreen obviously pregnant. Depicting pregnancy had been unacceptable on television. Although she won the battle, the network still did not let her use the actual WORD "pregnant" onscreen!
2) Lucille insisted that her husband, bandleader Desi Arnaz, play opposite her in the series--as "Lucy's" bandleader husband "Ricky Ricardo."
This was daring because Desi was obviously Latino and spoke with an definite Cuban accent. The network thought that some of the audience would be prejudiced, and would object to a mixed Latino/non-Latino couple.