[Name withheld], I appreciate your comment, particularly about the Gospel of Luke. I 100% agree with this much: Mary’s comments seem strange and unlikely if she already had a sexual encounter.
Please consider 4 reasons why I think you are under-interpreting [Bruce] McConkie’s remarks:
1. The strength of McConkie’s comparison between the way men are begotten of mortal fathers. “Christ was begotten by an Immortal Father in the same way that mortal men are begotten by mortal fathers.” (Mormon Doctrine, 1979, pages 546-47)
2. Later in the same book he writes that Jesus “was begotten, conceived and born in the normal and natural course of events.” (1966, p. 742) It seems unlikely that McConkie would have viewed non-standard and abnormal ways of insemination in ~1966 as “the normal and natural course of events.”
3. He elsewhere connects this with his particular, reconfigured definition of “virgin.” While you and I agree that “virgin” speaks to the absence of relations / physical union altogether, McConkie seems to have thought of it in terms of the absence of relations with a particular kind of human (a mortal human). See Mormon Doctrine, 1979, pp 546-47; The Promised Messiah: The First Coming of Christ, p. 466; Doctrinal New Testament Commentary, vol. 1, p. 82.
4. McConkie’s remarks are consistent with remarks by other LDS leaders, who argue that “according to the flesh, [Heavenly Father and Mary] have been associated together in the capacity of Husband and Wife.” (“The Seer”, pp. 158-9; cf. B. H. Roberts, “Defense of the Faith and the Saints”, vol 2, p. 270). Apostle Melvin J. Ballard on this same topic argues that the same “creative power and function” that carnal man uses as “a mere harp of pleasure”, God himself was able to use in a righteous way with Mary. (http://emp.byui.edu/marrottr/BegettingofJesusChrist.htm)
In the last part of your comment, you argue,
“Even if there was actual sex [between God and Mary], if Mary was completely unaware that anything had happened, certainly we’d call her a virgin anyway. You wouldn’t call a date rape victim unchaste.”
I have talked to many Mormons about this issue, but I have never heard this argument before. I am at a loss for words.
Before I read your comment and in light of the conversation, I went upstairs to find my copy of LDS author Bruce E. Dana’s book, Mary, Mother of Jesus (2001), which I purchased at a BYU Bookstore (next to Cougareat) a few(?) years ago. Chapters 11-14 (pp 47-62) argue that the Father, who has a resurrected, glorified body, associated in the capacity of husband with Mary in a natural course of events. Also, that she was empowered to physically withstand his presence by the Holy Ghost, and did so without shame, coercion, or hesitancy. Perhaps you will at least find it useful to see how LDS authors like Bruce Dana deal with the evidence and make sense of it.
I believe in the more traditional idea of the virgin birth — there was zero male participation or physical contact or DNA contribution needed. Much like Genesis 1, it was an act of creation requiring no physical contact or sexual union, accomplished by the effortless, omnipotent word of God. The significance of the virgin birth is that God, who is entirely a different species than us, condescended in love to become one of us. The Word became flesh — beautiful and awesome.