This came up in a chat with my friend and now im just curious to know more. Not pregnancy related to me really, just wanted to understand the story properly. Anyone knows?
Thats a religious belief from the Bible, not a medical thing dear. If you want details its best to ask in a faith group or read about it. Here we mostly talk pregnancy and baby stuff.
This is a matter of faith, believers say it was through the Holy Spirit, a miracle. Its something each person holds in their belief. Whatever you believe, stay positive and be at peace.