Did Jesus Have Siblings?

In Roman Catholicism, there is the belief that Mary was a perpetual virgin. This is the idea that Mary stayed a virgin for the rest of her life, never boring any other children.

The Greek Words

Throughout the Bible, Jesus is said to have "ἀδελφὸς", commonly translated as brothers. As the Gospel of Matthew states: "Is not this the carpenter’s son? Is not His mother called Mary, and His brothers, James and Joseph and Simon and Judas? And His sisters, are they not all with us? Where then did this man get all these things?” (Matthew 13:55-56 NASB1995). The problem with this is the Greek is too vague to make a definite statement. The word "ἀδελφὸς" or "brother", has a great level of nuisance. It can mean of course a brother, but also a relative, someone of the same race, someone of equal rank, a friend, or a fellow Christian (Mounce 117). Due to this range of definitions, we can not be certain which is the correct usage.

As for the term for "sister" or "ἀδελφή", this term is also very vague. It can mean a sister, a close family member, and a fellow Christian (Mounce).

The Early Church

The early church, as in most aspects, are not in a consensus on this topic. Jerome wrote: "But as we do not deny what is written, so we do reject what is not written. We believe that God was born of the Virgin, because we read it. ... You say that Mary did not continue a virgin: I claim still more, that Joseph himself on account of Mary was a virgin, so that from a virgin wedlock a virgin son was born," (The Perpetual Virginity of Blessed Mary, against Helvidius, Ch. 21).

Clement of Alexandria also wrote: "But, as appears, many even down to our own time regard Mary, on account of the birth of her child, as having been in the puerperal state, although she was not. For some say that, after she brought forth, she was found, when examined, to be a virgin. Now such to us are the Scriptures of the Lord, which gave birth to the truth and continue virgin, in the concealment of the mysteries of the truth," (The Stromata, Book 7, Ch. 16).

Athanasius also wrote: "For therefore the union was of this kind, that He might unite what is man by nature to Him who is in the nature of the Godhead, and his salvation and deification might be sure. Therefore let those who deny that the Son is from the Father by nature and proper to His Essence, deny also that He took true human flesh of Mary Ever-Virgin," (Discourse 2, Ch. 70).

Contrary to Jerome, Clement, and Athanasius, Tertullian wrote: "It is clearly more credible that, being certain that He had both a mother and brothers, they tested His divinity rather than His nativity, whether, when within, He knew what was without; being tried by the untrue announcement of the presence of persons who were not present," (On The Flesh of Christ, Ch. 7).

Conclusion

The Greek of the passages is far too vague to make a definite statement while the early church is contradictory. Based on this data, there is no conclusive evidence to say.

References:

Mounce, William D.. Basics of Biblical Greek Grammar: Fourth Edition. United States, Zondervan Academic, 2019.

"The Early Church Fathers and Other Works" by Wm. B. Eerdmans Pub. Co. in English in Edinburgh, Scotland, 1867.

Translated by John Henry Newman and Archibald Robertson. From Nicene and Post-Nicene Fathers, Second Series, Vol. 4. Edited by Philip Schaff and Henry Wace. (Buffalo, NY: Christian Literature Publishing Co., 1892.) Revised and edited for New Advent by Kevin Knight. <http://www.newadvent.org/fathers/28162.htm>.

Translated by William Wilson. From Ante-Nicene Fathers, Vol. 2. Edited by Alexander Roberts, James Donaldson, and A. Cleveland Coxe. (Buffalo, NY: Christian Literature Publishing Co., 1885.) Revised and edited for New Advent by Kevin Knight. <http://www.newadvent.org/fathers/02107.htm>.