Daughter of Data. Data constructed this Soong-type android in 2366, basing much of her programming on himself (she also had a positronic brain, for example). Lal's programming quickly surpassed her father's, though — she even experienced emotions, such as love, fear and sadness. Guinan allowed Lal to work in Ten-Forward so that she could study socialization and humanoid behavior.
After hearing of this unauthorized experiment, Admiral Haftel ordered Data to turn Lal over to the Daystrom Institute annex, but Data felt that it was his responsibility to care for Lal. Before this issue could be resolved, Lal experienced a fatal system-wide failure after experiencing an overwhelming range of emotions. Though Haftel joined Data in attempting to repair Lal, their efforts were fruitless, and the android shut down. Data transferred Lal's memories to his own brain.