Objections to the rather plain evidence for the existence of Jesus' siblings come almost exclusively from followers of the Roman Catholic and Eastern Orthodox churches, and  for one reason: in order to uphold the dogma of the perpetual virginity of Mary. If Mary always remained a virgin, then she obviously could not have had any children other than Jesus (unless Mary had multiple virgin births!). Protestants, on the other hand, have accepted that Jesus did have four brothers and at least two sisters based on the evidence of Mark 6:1-3 (see THE EVIDENCE ). In the Protestant view, Jesus is the oldest child, and following his birth Joseph and Mary had normal conjugal relations. Thus Protestants can hold to the dogma of the Virgin Birth, but do not hold to the perpetual virginity of Mary.

One commonly heard attempt to explain away Jesus' brothers is that they were Jesus' spiritual brothers, i.e., his disciples. This explanation is done in by the fact that there are passages where the disciples are clearly distinguished from Jesus' brothers, as for example, Act 1:12-14, 1Corinthians 9:4-6, and 1 Corinthians 15:5-7 (see REBUTTALS ).

The Roman Catholic and Eastern Orthodox churches have two different explanations of who the "brothers and sisters" mentioned in the New Testament are:

The Roman Catholic view is that the "brothers" and "sisters" mentioned in the New Testament are actually Jesus' cousins. This view is called the "Hieronymian Theory" by scholars and was originally proposed by Jerome. The weakness of this theory is that there was a perfectly good Greek word for cousins (anepsios) which is never used in the New Testament. Instead the Greek word for "brother" (adelphos) is used consistently. Another weakness of this theory is that whenever Jesus' brothers are mentioned in the gospels, they are almost always in the company of Jesus' mother, which would seem unusual if they were Mary's nephews.

The Eastern Orthodox way around this is to claim that James et.al. were step-brothers and sisters of Jesus. This is known as the "Epiphanian Theory" after its champion, the 4th century bishop Epiphanius. According to this view, Joseph was much older than Mary and was a widower when he married her. The brothers and sisters mentioned in the New Testament are thus Joseph's children from a previous marriage.

But there are three passages in the gospels that belie both these theories, and indicate that Joseph and Mary had normal conjugal relations like any married couple after the birth of Jesus: Luke 2:7, Matthew 1:18, and Matthew 1:24-25 (see REBUTTALS).