Henrietta Lacks (born Loretta Pleasant; August 1, 1920 - October 4, 1951) was an African-American woman whose cancer cells are the source of the HeLa cell line, the first immortalized cell line and one of the most important cell lines in medical research. An immortalized cell line will reproduce indefinitely under specific conditions, and the HeLa cell line continues to be a source of invaluable medical data to the present day. Lacks was the unwitting source of these cells from a tumor biopsied during treatment for cervical cancer at Johns Hopkins Hospital in Baltimore, Maryland, U.S., in 1951. These cells were then cultured by George Otto Gey who created the cell line known as HeLa, which is still used for medical research.

Henrietta Lacks was born Loretta Pleasant on August 1, 1920, in Roanoke, Virginia, to Eliza and Johnny Pleasant. Her family is uncertain how her name changed from Loretta to Henrietta, but she was nicknamed Hennie. When Lacks was four years old in 1924, her mother died giving birth to her tenth child. Unable to care for the children alone after his wife's death, Lacks' father moved the family to Clover, Virginia, where the children were distributed among relatives. Lacks ended up with her grandfather, Tommy Lacks, in a two-story log cabin that was once the slave quarters on the plantation that had been owned by Henrietta's white great-grandfather and great-uncle. She shared a room with her nine-year-old cousin and future husband, David "Day" Lacks (1915-2002).  Like most members of her family living in Clover, Lacks worked as a tobacco farmer starting from an early age. In 1935, when Lacks was 14 years old, she gave birth to a son, Lawrence Lacks. In 1939, her daughter Elsie Lacks (1939-1955) was born. Both children were fathered by Day Lacks. Elsie Lacks had developmental disabilities and was described by the family as "different" or "deaf and dumb".  On April 10, 1941, Day and Henrietta Lacks were married in Halifax County, Virginia. Later that year, their cousin, Fred Garrett, convinced the couple to leave the tobacco farm in Virginia and move to Maryland where Day Lacks could work at Bethlehem Steel in Sparrow's Point. Not long after they moved to Maryland, Garrett was called to fight in World War II. With the savings gifted to him by Garrett, Day Lacks was able to purchase a house at 713 New Pittsburgh Avenue in Turner Station. Now part of Dundalk, Turner Station was one of the oldest and largest African-American communities in Baltimore County at that time.  Living in Maryland, Henrietta and Day Lacks had three more children: David "Sonny" Lacks Jr. (b. 1947), Deborah Lacks Pullum (born Deborah Lacks; 1949-2009), and Joseph Lacks (1950). Henrietta gave birth to her last child at the Johns Hopkins Hospital in Baltimore in November 1950, four and a half months before she was diagnosed with cervical cancer. Around the same time, Elsie Lacks (Henrietta and Day's daughter born in 1939), was placed in the Hospital for the Negro Insane, later renamed Crownsville Hospital Center, where Elsie died in 1955.

Did she have children?
In 1935, when Lacks was 14 years old, she gave birth to a son, Lawrence Lacks.