That did seem to make the most sense. And now that I'm thinking on it, hormone's probably have subtle affects on just about just about every aspect of the human body. I'll try to look into hormonal influences after I've finished researching erythroid colony development.

And you're right! It would be fascinating to see these studies performed on human subjects, but I imagine they might be having trouble finding volunteers. The studies wouldn't be at all effective if the were performed on cadavers, would they?