Could God have planted the embryo of Jesus in a stained, faulty, sinful container.....I guess He could have, but why would He have insulted His son by doing so when it was very easy for Him to create a PERFECT container
Like most of the novel Marian doctines, the Immaculate Conception of Mary, is derived at by deducing what would be fitting for God to have done, and presto the guess becomes dogma.
Strange that being born of a virgin, who needed a savior, is an insult by God? But being beaten, scorned, spit on and murdered, shamefully, by sinful men on false charges while being sinless and innocent is not an insult?
James 1:12 - those who endure will receive the crown of life which God has promised. Mary has received the crown of life by bringing eternal life to the world.