In The Offspring, widely considered one of the most memorable and moving episodes of Star Trek: The Next Generation, Data, having recently attended a cybernetics conference where a new sub-micron matrix transfer technology was introduced, returns to contruct an android and transfer his own positronic pathways to the new android's brain. Data names the android "Lal," which we learn means "beloved" in the Hindi language, and introduces it to his friends on the Enterprise crew as his child.
Picard is dismayed by Data's decision to pursue such an undertaking in secrecy and is extremely concerned about the reaction when Starfleet learns of the existence of another Soong-type android. However, Data is determined, and goes immediately to work in raising Lal. Lal's personality and sentience develop steadily, to everyone's delight. Although Lal encounters difficulties in mastering the nuances of human behavioral norms, she displays emotional and functional abilities that surpass Data's, including the use of verbal contractions. In response to Lal's "frustration" at her challenges, Data explains that although neither of them may become fully human, the struggle itself can bear worthwhile fruits.
Admiral Haftel arrives from Starfleet Research, interviews Lal, and insists that she be relocated (without Data) to the Daystrom Annex on Galor IV. Upon learning of Admiral Haftel's plan, Lal goes to Deanna Troi and tells her that she is scared. Troi immediately senses the authenticity of Lal's newly found emotion, then watches in dismay as Lal begins a difficult retreat to Data's laboratory. Troi summons Data to his laboratory, where Data (with Admiral Haftel's assistance) struggles unsuccessfully to save her from her rapid positronic cascade failure. In her last moments of life, Lal expresses sadness that Data is unable to save her, but thanks him for her life and tells her she loves him. Data isn't able to feel the emotion of love, so Lal tells him that she will feel it for them both. Lal suffers complete neural system failure—dies—a little more than two weeks after her activation.
The Offspring is also notable in that it was the directorial debut of Jonathan Frakes.