This I know.
For the Bible tells me so.
The Bible says Jesus was “like us in every way” yet was without sin. So, the fact that Jesus could sin is indisputable; he wasn’t guilty of Mary’s sin because while Mary certainly passed on her human/sinful nature to Jesus HE NEVER OBEYED IT. He was without sin. Therefore no judgement nor guilt.
Acts 6:8 refers to Stephen as plErEs charitos, which literally means "full of grace" and just the same as the description used of Jesus in John 1:14.
So if Catholics insist that Mary was sinless because of the use of kecharitomene they must also believe that Stephen was also sinless since the version of the word charitos along with the word plErEs gives Stephen the same full of grace as Jesus but does not give that to Mary.