Why are you bringing the Mormons into this? (That is, are you from that background or something?)
I fear you are starting off with the wrong terminology, so I will correct you gently. The Immaculate Conception is indeed a Catholic only belief. But you are not talking about the Immaculate Conception.
You are talking about the Virgin Birth, how Jesus came to be in Mary's womb without her having sex. How Mary came to bear the Son of God, how she was "overshadowed by the Holy Spirit" and found herself pregnant.
The Immaculate Conception refers to something else completely, the conception of Mary in her mother (St. Anne)'s womb.
Back to our story
The Mormons if I remember right claim that Joseph is the father of Christ by way of the flesh but God is father by way of the spirit. Why does both Matthew (1.1) and Luke (3.23) trace Christ genealogy through Joseph back to King David unless both assumed Joseph to be the father?
The Mormon's claim many things which fall outside of what is generally accepted as "small o" orthodox Christianity.
Joseph is the adopted father of Jesus, raised as his own. Joseph made absolutely no genetic or otherwise contribution to the creation of Jesus in the womb. He served as father of the boy from birth to death.
If Joseph was not the father then it would seem that Jesus does not fulfil biblical prophecy of the Messiah being a descendant of David because the ancient Hebrews did not recognize the maternal genetic contribution of the women and no mention of Mary’s lineage is given.
This is the argument our Jewish friend likes to make to us to dispute the entire idea of Jesus being both messiah and Son of God. We Christians just accept the heritage through the adopted father Joseph.
The only reference I find to the idea of Immaculate Conception is Matthew (1.18). My Revised Standard Version says that after Joseph and Mary were betrothed but before they came together Mary was found to be with child. Which could be interpreted as before Joseph and Mary started to live together but not necessarily before they had sex, although their act would have been a sin and caused Joseph the shame described.
If you read Matthew 1:25 you see that Joseph "knew her not" till she had given birth. This is the clearest statement of the Virgin Birth. Joseph's shame was that he would be accused of fornication (if he did it) or that he selected a woman of loose morals (if she was sleeping around) for his betrothed.
SD
You really don't understand the idea of an infallible Church. You might as well ask what I would do if tomorrow the Church announced that this "Jesus thing" was just a lark. "Everyone go back to being Jews." Won't happen. Can't happen. Try to understand that for a minute. SD
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The "infallible Church" has never declared "infallibly" that women cannot be ordained. There are very, very few "infallible" declarations.
Can happen. May happen.
Married clergy: Can happen. Will probably happen.
There is no biblical prohibition to women clergy. It is nothing but "tradition".