If Mary was “conceived without sin” and “is the ever perfect, ever virgin Mother of God” because God chose to have it that way, why couldn’t JESUS be born without sin because God chose it that way?
Jesus was going to be born without sin no matter what. It would have been inappropriate for the vessel through which He came to be tainted. Everything Catholics believe about Mary boil down to, Because Jesus, therefore Mary. Mary has nothing outside the Will of God.