Board Thread:Speculation House/@comment-16502426-20131101024335/@comment-22580009-20131115060831

It's possible that she is still somewhat experimental, and therefor is the only one. They don't know what will happen and it takes so much money and time to make an android of that caliber that they only made one, and then observe her for flaws to fix. Though there could be other, somehwhat less developed prototypes, similiar to Data and Lore in Star Trek: TNG.