[metmom]

Mary’s preservation from original sin was accomplished in anticipation of her Son’s redemptive work.

And why was it necessary?

The gracious character of this blessing is also the reason that Anne and Joachim did not need to have it: It was a grace God could give to anyone at any time.

If God could do it for Mary, born of sinful parents, then He could have done it for Jesus, born of a sinful mother.

Why not? Sinless is sinless. If Mary was necessarily sinless to bear the sinless Christ, then why was it not necessary for Mary's parents to be sinless to be a fitting vessel to bear the (allegedly) sinless Mary?

[Elsie]

Well; she’s REALLY not THAT sinless...

[terycarl]

then why was it not necessary for Mary's parents to be sinless to be a fitting vessel to bear the (allegedly) sinless Mary?

The allegedly sinless Mary WAS NOT GOD....Jesus was.