I always understood the word "conceived" or "conception" to apply to the person being born, not the parent. Is this not accurate?
Yes, that’s how it’s being applied here, referring to Mary’s own conception. It’s a Catholic doctrine that essentially says God called the Mary constructor with a status override flag of “originalSin = false”, so that she would go on to be a fitting vessel to carry Christ later.
Oh, I understand now, thanks. So in theory, if Mary had had multiple children, it would have really messed up the idea of the Trinity (3)