Personally, I can take or leave Perpetual Virginity: no doctrines of the faith depend upon it. Yet I could not positively affirm it, because the scriptures make no affirmation. Likewise, the Immaculate Conception is a tough pill to swallow without scripture to back it up.
It also addresses the doctrine of her being bodily assumed into heaven instead of dying.
From the article:
"the doctrine of the Immaculate Conception ...from the first instant of her existence she was in the state of sanctifying grace and was free from the corrupt nature original sin brings"
Also:
The doctrine of the Assumption says that at the end of her life on earth Mary was assumed, body and soul, into heaven, just as Enoch, Elijah,