That's okay. I don't have to be right all the time to retain my paramount position. Embryology was never one of my interests. I mean, besides this separate circulation stuff (virtually separate, that is) I never knew that the placenta was a sin barrier. These threads are very educational.
If this is some sort of oblique reference to that Romania business, my home Atlas had been sabotaged by agents of Duane Gish.
Nor was I aware that sin was a substance that circulates in the blood and can contaminate other people through contact, as the author seems to believe.
Perhaps she should start with something easier to establish, like how many angels can dance on the head of a pin.