ANSWER: Several New Testament scriptures confirm the fact that Jesus was NOT the only child born into the family tree that begins with Joseph and Mary (contrary to what Catholics and other denominations may teach). In fact, Mary gave birth to a total of at least FIVE boys and at least two girls (Matthew 13:54 - 56, see also 12:47)! Please see our article on how the New Testament shows that Jesus did have brothers and sisters.
Accounts are sketchy as to what happened to the brothers and sisters of Jesus in his family tree after His resurrection. The Bible does give us, however, clues regarding what may have happened to his mother Mary. We find when he was on the cross that he commended the care of his mother into the hands of the apostle John (John 19:26 - 27).
In Raymond Capt's book, Traditions of Glastonbury: The Biblical Missing Years of Christ - Answered, he says that tradition states that John put Mary in the care of an uncle in the family, Joseph of Arimathea. He was believed to be a rich tin merchant who sailed to Britain shortly after the resurrection of Jesus and settled in Southwest England in a village called Glastonbury. This tradition holds that Mary lived there with a few other disciples for 15 years then died. Tradition also states her death occurred in 48 A.D.
Only some information could be found about two of the physical brothers of Jesus, James and Jude. The Bible's New Testament mentions four men named James. The first James is the son of Zebedee and Salome (cf. Matthew 27:56 with Mark 15:40) who is the Apostle John's older brother (making him a cousin of Jesus). This identifies Zebedee and Clopas as being the same individual. The second James was a son of Alpheus, who was one of the disciples of Christ. It is not at all clear whether this is the same James as the one related to Zebedee.
The third James found in the Bible is the father of the Apostle Judas, (not Iscariot who betrayed the Lord) who is referred to in Luke 6:16 and Acts 1:13. Nothing else is known of him. The fourth and final person named James is a member of Christ's family tree. The Apostle Paul wrote in 1Corinthians 15:7 that the first post-resurrection appearance of the risen Christ was to James, who from that time forward gave his life to Christ. James was an early leader of the Jerusalem Church. The last Biblical mention of him is in Acts 21:18 where the Jerusalem elders exhorted Paul to take a Nazarite vow.
Jude, another brother in the family tree of Jesus, also did not believe in him until after His resurrection. Jude is the author of the Epistle that bears his name. No more information exists about the two remaining brothers of Joseph and Simon. The book of Matthew states that the Lord had at least two sisters in the family named Mary and Salome. Parallel accounts in Matthew 27 and Mark 15 link Mary and Salome (Matthew 27:55 - 56).
Are there people living today who are in the family tree of Joseph and Mary, the blood relatives of Jesus? Given that Mary had at least SIX children other than our Savior that lived to adulthood, there is a high degree of probability at least a few people living today have a genetic link to him.