If Mary is as thought "a virgin" and the thought that to fulfill the Old Testimony prophesy, Jesus must be born of a virgin because a virgin is sinless.

My question is , "how does virgin lead to sinless"?

I guess it is what you mean as sin.

Anyone want to explain this?

Seems this progressive Anglican church in New Zealand had caused a stir with a billboard with the caption "Poor Joseph. God is a hard act to follow."

Church web page:

http://www.stmatthews.org.nz/nav.php?sid=498&id=999

News story here:

 http://www.seattlepi.com/national/1104ap_as_new_zealand_church_billboard.html

The straight question: was Jesus the son of God in terms of Science? Straight answer: No, in my opinion.

In Biblical times the word virgin had nothing to do with sex. At that time virgin meant not married.

Jesus was not the genetic son of God. However Jesus was right to say that he was the son of God. We are all the children of God, just as any adopted child is the son or daughter of their adopted parents.