Here’s a poignant insight from Martyn Lloyd-Jones regarding Christmas:
What is taught in Scripture is not that Mary had been either born or made sinless, but that portion of Mary, that cell out of Mary that was to be developed into the body of the Son of God was cleansed from sin; and that only.
So Mary remained sinful, but this portion that she transmits to her Son has been delivered, set free from sin; and it is to that that the Son of God is joined. That is the human nature He takes unto Himself. It is a miracle, of course; and we are told specifically that it is a miracle. It was because she did not realize that a miracle was to happen that Mary stumbled at the announcement of the Archangel Gabriel, and his reply to her is: “Do not try to understand this. The power of the Highest shall overshadow you, the Holy Ghost will come upon you, you are going to conceive of the Holy Ghost” – who has power to work this cleansing so that the body of the human nature of the Son of God who is to be born of you shall be entirely free from sin.
So we reject the so-called doctrine of the “Immaculate Conception”; but we assert with all our power the doctrine that the human nature of the Son of God was entirely free from sin.
GRACE & PEACE 
I think this covers an issue that is still a mystery Dennis. That Jesus being made flesh (a man) and tempted in all ways yet without sin. Fully man, yet fully God as well, is a mystery to us.
Don’t think any specific cells in Mary (her flesh) were made sinless as such, but a miracle of God, the Holy Spirit touched her body to concieve & bring Jesus into the world.
Did Jesus have the capacity to sin as a man ? I think so…Did He have a sinfull nature (the old man) to deal with ? The Bible tells us he was tempted in all points as we are yet without sin…He knows our struggles with sin, because He experienced it. Yet without sinning. I’d say He did not have a sinfull nature as we, yet still experienced being tempted. Now if he were born of a result of natural union with Mary that would have been a different story, yet even that God could have overcome as He is God.
This line of communication, “Do not try to understand this,” was understood to life understanding from fragmented areas of nervous system information at an unacceptable activity place.
This line of communication, “Mary stumbled at the announcement of the Archangel Gabriel.” was also understood to someone at an unacceptable activity place.
The only life set down in confusion is life understanding it’s experiences and knowledge as from humans or TV sets that are not understanding God’s continuable activity and interest. God provides continuous understanding ability and Mary had and continues to have this position mark. As someone(s) at an activity place that is to be a good shepherd, you can use yourself united as always this way. It is Mary’s position mark that you understand and translate God through to life that will say and do what is loved. As sitting up and always understanding circumstances, you are to united at predestined areas of whole nervous system information for the provision of continuous united interest and the provision of immediate knowing about what you see. What you will see is what God is causing God to see and this is what is interesting to God now, now, and now.
There is something else to be said, you can use this information.