Was mary human or not? lmao If she wasn't human, then sure, she could have been perfect and sinless, but alas she was but a human woman.
Even worse, if mary is perfect and sinless from whence does she come? And her mother, was she perfect and sinless? and her mother, and so on and so forth ad Infinium? Oops.
Sounds more so like an overall issue with rcc concept of God's sovereignty and power, and trying to "fix" what is meant to be mystery into something that quickly causes error.
