Jesus is fully man, and fully God.
I believe it is true that: the Holy Spirit's seed and Mary's seed produced Jesus?
For Jesus to be sinless, would Mary need to be either:
a) Saved and or Filled with the Holy Spirit
b) Sinless
I can't see, God in the flesh could be conceived if Mary was a sinner.
From what I have read in the bible genealogical cures and/or sins is passed down by the Fathers of those children/generations.
Exo 20:5 Thou shalt not bow down thyself to them, nor serve them: for I the LORD thy God am a jealous God, visiting
the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me;
Exo 34:7 Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the
iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation.
Num 14:18 The LORD is longsuffering, and of great mercy, forgiving iniquity and transgression, and by no means clearing the guilty, visiting
the iniquity of the fathers upon the children unto the third and fourth generation.
Deu 5:9 Thou shalt not bow down thyself unto them, nor serve them: for I the LORD thy God am a jealous God, visiting the
iniquity of the fathers upon the children unto the third and fourth generation of them that hate me,
This being said: with the seed of the father having been from God, that seed is without sin, and Jesus The Christ adopted God's sinless nature. Sin in the bible is passed down by the Father. Mary's sin would not be applicable.
We also have an account of Mary admitting she indeed needed a savior:
Luk 1:46 And Mary said, My soul doth magnify the Lord,
Luk 1:47 And my spirit hath rejoiced in God my Saviour.
Luke 1:48 For he hath regarded the low estate of his handmaiden: for, behold, from henceforth all generations shall call me blessed.
Firstly, all men have sinned, including Mary, and fallen short of the glory of God [Rom 3:23], and through one man sin entered the world and death spread to all men [Rom 5:12]. King David writing in Psalms says that he was brought forth in iniquity and in sin when his mother conceived him - biblical proof of mankind's sinful nature
from the time of conception.
So, again... since Mary "conceived by the holy spirit". (Mat 1:20, Luke 1:35) Jesus did not receive Man's sinful seed, but God's sinless one. And again, that had nothing to do with Mary.
[Psa 51:5]. According to the law of Moses every mother that conceived, either a male or female, had to after an appointed time offer sacrifices to God: one as a burnt offering, and one as a sin offering [Lev.12]. Mary, after conceiving Jesus made these sacrifices in accordance and obedience to the Law God gave to Moses. This is clearly indicated to us in the book of Luke chap. 2 ver. 21-24, as Mary applies this very observance as is required of every Jewish woman who conceives her first born son. Read Leviticus 12 is first, understand what is being said, then read Luke 2:21-24. Once reading and understanding what is being said, it is clear that the offering Mary offers makes according to ... law of the Lord, A pair of turtledoves, or two young pigeons. [Lk.2:24], ... the one for the burnt offering, and the other for a sin offering: ... [Lev. 12:8]. The sin offering Mary gives is sufficient evidence Mary's carnality.
The Scriptures also categorically state the family Jesus had, and that Mary did conceive after the birth of Jesus. She never remained a virgin, and can never be considered "immaculate" as the Roman Catholic Church has exalted her to be. "Is not this the carpenter's son? is not his mother called Mary? and his brethren, James, and Joses, and Simon, and Judas? And his sisters, are they not all with us? Whence then hath this man all these things?" (Mat 13:55,56).