Q
I believe the entire sperm and egg, were from God and included no part of Mary or man (or angel) or the line of sin through Adam and Eve.
A
If Jesus wasn’t God, His sacrifice on our behalf couldn’t have paid the penalty for our sins. If He wasn’t a man, He couldn’t have been our Kinsman Redeemer. Only with God as His father and Mary as His mother (Luke 1:31-32) could He accomplish this. Also, Jesus had to be biologically related to Mary to be of the house of David and have a legal claim to David’s throne (Luke 1:32, Luke 1:69).