What? This doesn't make any sense. Christ is sinless because He is divine.
It has nothing to do with having "impure progenitors" and even if it did how would impurity lead to sinlessness?
Did you miss a double negative somewhere?
then by reasoning,
Ahem
Mary is better than Christ because she could overcome having an impure lineage.
Mary didn't "overcome" anything. She was gifted by God through the graces available from the one Sacrifice of Christ on the Cross.
By RC reasoning (that Jesus had to have some help in coming from a sinless mother)
Please, I beg you, do not go around making claims about what Catholics believe. You are confused and are not anywhere near presenting what it is we profess.
Educate yourself.
Jesus didn't need help and we don't teach that He "needed" to have a sinless mother in order for Him to be sinless.
You are simply wrong about what we believe.
HE sure needs it NOW!!!
HE is SO overwhelmed by Prayers that His Mother has to filter through them!!