I make this post to provide additional insight regarding a similar post that was made by someone else earlier in the day.

1) Mary's virginity was nothing extraordinary in the early Jewish culture or in her era. The vast majority of unmarried Jewish young women in those days were virgins. In fact, Jewish customs feature lots of incentives and anti promiscuity policies that compel young women to generally remain chaste until marriage. So, in a general sense, Mary's sexual purity was a given societal norm and not a qualifier.

2) The major reason Jesus was ordained to be conceived by a virgin via the agency of the Holy Ghost was for one reason and one reason alone: To escape the ancestral paternity and natural heredity of the genes of the First Adam. (See Romans 5:12-21)

He was not tainted by, nor did he inherit the original sin. That's why he had to come through a virgin so that his birth would not be by the will/sperm of man but by the word and power of God. This is what qualified him to take away the sins of the world. His bloodline was pure. (See John 1:12-14)

Unlike every other person that has ever been born or will ever be born into the earth, Jesus did not inherit the original sin of Adam. He had no sin or blemish whatsoever. He was just like that sheep that took the place of Isaac on the mountain. This is why he's called the Last Adam. (See 1 Corinthian 15:45-49)

3) Another reason Mary was chosen (in addition to the sovereign mercy and providence of God) was because of her lineage. Both she and Joseph were descendants of David. This is actually why Jesus was born in Bethlehem. And God made a vow to place the eternal king (Jesus) on the throne and dynasty of David forever. This is why Jesus is called the Son of David, and the One who holds the Key of David. ( See Jeremiah 33:14-23; Matthew 21:9; Revelation 3:7)