Board Thread:General Discussion/@comment-1210805-20130313135030/@comment-1672596-20130329114858

The novelization did hint that they didn't get any of them right until the ninth batch, and Liquid did imply there were other clones besides himself, Solid Snake, and Solidus that had existed but perished. MGS4 even mentioned that they had "countless failures" before they brought about Solid and Liquid Snake. Assuming they did the exact same procedure every time, that would mean they created at least 72 fetuses by the time Liquid and Solid Snake were born, including the ones aborted to promote fetal growth for the Twin Snakes.

As far as the patients, I'm not sure they were all Mother Base patients. I don't think Miller was among them in the TPP scenes (by that, I mean the events of the hospital attack). Actually, I remember someone mentioning that the hospital was located on a certain island near Cyprus.