Star Trek: 10 Things You Didn't Know About The Soongs

We learned in the Next Generation episode Inheritance that Noonian Soong did not actually create his androids alone, in fact the science was perfected with the help of a woman he met, then later married, on Omicron Theta. Her name was Juliana Soong, and she was effectively the mother of Data and the other androids.

She was fatally injured during the attack on the colony by the Crystalline Entity, but Noonian, unwilling to lose her, constructed his most advanced android body yet, a complete recreation of Juliana's body, and transferred her memories into it.

This seems to be an early version of the technology that would eventually be used to resurrect Jean-Luc Picard. Her new body would register as Human on scans and transporters, her hair would grow naturally, and she would eventually die after living a full Human lifetime. The only addition Noonian made was making Juliana unaware that she was in an android body, and programming her to shut off if she ever found out. Her body also contained a secret holographic program of Noonian that could explain what happened to her and answer any questions if this happened. Data recieved this message and oddly chose not to reveal the truth to Juliana.