The Catholic and Orthodox doctrine of the perpetual virginity of Mary contradicts the Bible.

The doctrine of Mary's perpetual virginity is a core belief in the Roman Catholic Church and the Orthodox Churches. It states that Mary—the mother of Jesus—was and remained a virgin before, during, and after the birth of Jesus. The Catholic Church has officially established this belief as a binding doctrine of faith. This teaching falls within the field of so-called Mariology, which is the theological study of Mary. It also includes the belief in the virgin birth of Jesus. The video below presents a critique of this doctrine.

More about the doctrine of the perpetual virginity of Mary can be found in the following Wikipedia article: https://en.wikipedia.org/wiki/Perpetual_virginity_of_Mary