Soong-type android

A Soong-type android is an artificial life form first developed by Dr. Noonien Soong. They are distinct from other androids by virtue of their positronic brains, which are considered complex enough to permit the rise of sentient thought.

Soong's first prototype android was named B-4. The next was Lore, who was deactivated after endangering the Omicron Theta colony. Data was the most Soong's most noteworthy androids, and who established the rights of androids as sentient beings. Soong secretly built an even more advanced android, giving it both the form and the memories of his wife, Julianna Trainor. Data was able to partially duplicate Soong's work by creating an android daughter named Lal. 

Others attempted to duplicate Soong's work, including Dr. Bruce Maddox and Lars Patek