Star Trek: 10 Things You Didn't Know About The Soongs
3. Why Noonian Soong Modelled His Androids After Himself
When Data questioned Noonian on why he decided to make him in the Next Generation episode Brothers, Noonian compared his creations to an act of self-preservation akin to having a child.
In the same way that, by reproducing, people can gain a sense of immortality knowing that some essence of them remains, Noonian viewed Data as an extension of himself. Something (or rather, someone) who would be remembered long after he was gone.
With this in mind, it's easy to see why Noonian based his androids off of himself. His wife, Juliana, originally wanted Data to appear female (as opposed to the earlier androids like B-4 and Lore), but Noonian quickly dismissed the idea and constructed Data's head in his own image without her knowledge.
We saw something similar with Dr. Lewis Zimmerman from Voyager, who based his Emergency Medical Hologram programs off of his own appearance, though for Lewis this backfired when the Mark I EMH's became outdated and he instead became the face of millions of dilithium miners.