[JCBreckenridge]

“It is all throughout the Bible of the sinful nature of man. We are born into sin.”

So there is no direct reference to Mary having sinned.

Why, then, do you believe this is so?

Nobody questions that David is a sinner - because his sins are documented. Why is Mary’s sin not documented?

[RegulatorCountry]

So there is no direct reference to Mary having sinned.

She referred to Jesus as her Savior. That is direct evidence. No need of salvation if one hasn't sinned.

[BipolarBob]

"So there is no direct reference to Mary having sinned. Why, then, do you believe this is so?
Why is Mary’s sin not documented?"

Now you're going all Dan Brown on me with this. I'm supposed to prove a negative. No thanks. Lots of people in the Bible do not have their sins documented. Proves nothing. The burden of proof is on YOU.