The short answer to this question is that Jesus did not have any full-fledged biological brothers or sisters. This is because of the nature and circumstances by which Jesus was conceived. It was unlike any other conception in the history of humanity. The Bible tells us that while Mary was engaged to be married to Joseph, she became pregnant. Mary told Joseph that the Holy Spirit had impregnated her. Joseph didn't believe her. Can you blame him?

However, Joseph, being a good and just man, didn't want to shame Mary. He also didn't want to marry her because he believed, as any normal human being would believe, that she had been unfaithful to him with another man. Nevertheless, in a dream, the Lord revealed to Joseph that the child Mary was carrying in her womb was, in fact, from the Holy Spirit.

This astonishing revelation, revealed to Joseph by an angel from God in a dream, was enough for him to trust God and take Mary as his wife. Yet the Bible says that he didn’t know Mary as his wife until after she gave birth to Jesus.

The Unique Conception of Jesus

No one else in the history of humanity can say that is how they were conceived. Mary is the only one to ever give birth to a child conceived by a woman and God. This may be unfathomable for some, but it is, nonetheless, the truth of the story of Jesus as recounted in the Gospels.

Because Jesus was conceived by the Holy Spirit and born of a woman, he was unique. He was born with a human and a divine nature. He was fully human and yet fully God. No other human in the history of the world can legitimately claim such a fact in their lives.

Did Jesus Have Full Siblings?

So, in short, Jesus did not have any full brothers or sisters because no one else was conceived like He was. With this uniqueness, some Christian faith traditions have espoused that Mary was not only a virgin when she gave birth to Jesus but that she was a virgin when she died.

The Bible doesn’t suggest Mary’s birth was anything but a normal human birth. The idea of the perpetual virginity of Mary is unbiblical. Matthew 1:25, speaking of Joseph, declares, “But he had no union with her until she gave birth to a son. And he gave Him the name Jesus." The word "until" indicates that Joseph and Mary did have normal sexual relations after Jesus was born. Mary remained a virgin until the Savior's birth, but later, Joseph and Mary had several children together.

Biblical Evidence of Jesus' Siblings

We have evidence throughout the Bible that, after Jesus was born, Joseph and Mary had other children besides Jesus. Contrary to some traditions in the Christian faith, Mary did not live as a virgin all her life and thus neither did she die a virgin, as some Christian traditions might argue. The Bible would argue the contrary. Matthew 13:55 tells us that Jesus had four brothers: James, Joseph, Simon, and Judas. Matthew 13:56 tells us that Jesus had sisters, but they were not named or numbered. His brothers are mentioned several times in the Bible, and Mark 3:31 tells us that Jesus’ mother and brothers came to see Him.

One time, Mary and Jesus' brothers came to see him. It appears they may have been a bit angry with him and told the disciples to let Jesus know his mother and brothers were waiting outside for him. This is when he retorted, "My mother and brothers are those who do the will of the Father." It would appear there had been some tension between Jesus and his mother and brothers. But the point is well taken. Jesus considers his family to be ultimately not just biological but, more importantly, spiritual—specifically, those who do what God tells them to do with their lives.

Jesus’ Teaching on Spiritual Relationships

One time, when Jesus was speaking, a woman in the crowd proclaimed, "Blessed is the womb that bore You and the breasts at which You nursed" (Luke 11:27). There was never a better opportunity for Jesus to declare that Mary was indeed worthy of praise and adoration. What was Jesus’ response? “On the contrary, blessed are those who hear the word of God and observe it” (Luke 11:28). According to Jesus, obedience to God’s Word was more important than being the woman who gave birth to the Savior.

Jesus' Brothers and Early Church Leadership

In John 7, Jesus’ brothers go on to the festival, and Jesus stays behind. In Acts 1:14, Jesus’ brothers and mother are described as praying with the disciples. In Galatians 1:19, Paul writes, “But I saw none of the other apostles except James, the Lord's brother.”

Probably one of the strongest arguments for Jesus having brothers is found in 1 Corinthians 9:5. The Apostle Paul says, “Do we not have the right to take along a believing wife, as do the other apostles and the brothers of the Lord and Cephas?”

Paul argues that the brothers of the Lord, meaning Jesus, took wives with them when they went to do ministry after his resurrection. Why would Paul make such a claim about the brothers of Jesus if he were not first speaking the truth and second referring to it as a means of authority to support his own ministry?

Did Jesus Have Siblings?

The massive evidence through the Gospels and the Epistles of Paul would seem to indicate that the early church had no problem believing Jesus was miraculously conceived, unique to Himself, and yet afterward, the evidence would equally point to the belief that Jesus had siblings. The only reason some faith traditions reject this view is that they have a doctrine built on the sinlessness of Mary, which would be refuted if Mary's virginity were not maintained until death.

Yet, there is no indication in the Bible that this sort of doctrine is essential for the Gospel of Jesus Christ and eternal faith through Him to be established for a person’s life.

Therefore, the most natural conclusion of these passages is to interpret that Jesus had actual blood half-siblings but no full siblings.