The Bible often refers to the “brothers” and “sisters” of Jesus, so how can we believe that Mary remained a virgin and did not give birth to other children? In the Bible, the word brother or sister is not just used to refer to children of the same parents (as we do today).
In the Bible, “brothers” can also be cousins, nephews and uncles, and “sisters” also cousins, nieces and aunts. Jesus calls us all brothers and sisters. The mutual bond between Christians is not based on blood ties, but on following Jesus and thus becoming a brother or sister of Jesus, and therefore also of each other.