Andrea Pia Yates was born Andrea Pia Kennedy on July 2, 1964, in Houston, Texas. She was the youngest of five children in her family. Her mother, Jutta Karin Koehler, was a German immigrant, and her father, Andrew Emmett Kennedy, had Irish roots. Growing up, Andrea faced challenges with bulimia and depression as a teenager. At the age of 17, she confided in a friend about suicidal thoughts.

Andrea graduated high school in 1982 as the valedictorian of Milby High School. She was active in school life, serving as captain of the swim team and holding a position in the National Honor Society. After high school, she studied nursing and completed a two-year pre-nursing program at the University of Houston. She later graduated from the University of Texas Health Science Center at Houston.

For several years, Andrea worked as a registered nurse at the University of Texas MD Anderson Cancer Center, from 1986 until 1994. In the summer of 1989, she met Russell "Rusty" Yates, a NASA engineer, at the Sunscape Apartments in Houston. They soon moved in together and married on April 17, 1993.

The couple was very religious, following a devout evangelical Christian lifestyle. They expressed a desire to have many children and moved into a four-bedroom house in Friendswood, Texas. Their first child, Noah, was born in February 1994. After a brief move to Florida for Rusty's job, they returned to Texas after the birth of their third child, Paul.

After the birth of their fourth child, Luke, Andrea's mental health issues intensified. On June 16, 1999, Rusty found her displaying troubling behaviors. The following day, she attempted suicide by taking pills. This led to her hospitalization, where she was treated with antidepressants. Her condition showed improvement, but she struggled with her mental health.

In July 1999, Andrea experienced a severe mental breakdown, which included two suicide attempts. She was diagnosed with postpartum psychosis, a serious illness that can occur after childbirth. Despite warnings from her psychiatrist not to have more children, she became pregnant again and later gave birth to her daughter Mary in 2000.

Andrea's mental health declined further after the death of her father in March 2001. She stopped taking her medication and exhibited harmful behavior, leading to another hospitalization. On April 1, 2001, she was treated and released but faced a further deterioration in her condition by May of that year.

On June 20, 2001, Andrea Yates drowned her five children in their home in Clear Lake City, Texas. The children were Noah, John, Paul, Luke, and Mary. Rusty Yates, her husband, had left for work that morning. He left her alone with the children, although doctors had instructed that she should be supervised at all times.

Andrea first drowned Paul, Luke, and John, laying them on her bed afterward. She then proceeded to drown Mary, leaving her floating in the tub. When Noah entered and asked what was wrong with Mary, he ran away in fear. Andrea caught Noah and drowned him too, leaving him floating next to Mary in the tub. Afterward, Andrea called the police, requesting an officer without initially explaining why. She then called Rusty, asking him to return home immediately.

Andrea later confessed to the police about the drownings. Before her second trial, she revealed to a psychiatrist that she waited for Rusty to leave for work before filling the bathtub because she knew he would not allow her to harm the children. Following the murders, investigators found the family dog locked away, suggesting Andrea may have confined it to prevent any interference during the event.

In March 2002, a jury found her guilty of capital murder, but they did not choose the death penalty, resulting in a life sentence. However, this conviction was overturned in January 2005 due to false testimony during the trial related to a television show that did not exist. In January 2006, a retrial led to a verdict of not guilty by reason of insanity. Andrea Yates was then committed to a mental health facility for treatment and evaluation. She was later moved to another hospital, where she continues to reside.