Answer: John the Baptist (he was only referred to as such after he began to baptize) was born to a woman in her old age named Elizabeth. God, although she had been barren all her life, healed her so that she could produce a son (Luke 1:5 - 15, 36).
Elizabeth was a descendant of Israel's first high priest named Aaron (Luke 1:5) and a cousin of Jesus' mother Mary (Luke 1:36). Zacharias, the father, was a priest who served in Jerusalem's temple during Abia's course. This made John of priestly descent.
A Nazarite from conception
John the Baptist was set apart, for life, to be a Nazarite even before his conception (Luke 1:15). His miraculous birth, occurring just six months ahead of Jesus', took place in the late February to early March time frame (at the same period of God's Feast Days known as Passover and Feast of Unleavened Bread) in 5 B.C.
Not only was the Baptist's arrival a miracle, it was also a fulfillment of prophecies which spoke of a voice in the wilderness who would come in the spiritual power of Elijah (Matthew 17:10 - 13).
Nazarites were those who were consecrated to serve God and who were generally separated themselves from other people. John, as a Nazarite, was required to not drink any wine or strong drink, and could not even eat grapes or anything that had grapes in it. He also had to refrain from cutting his hair. Additionally, he could not come near or touch a dead body, even if it was his mother or father (Numbers 6:2 - 21).
His ministry and calling
John spent the early part of his life dwelling in the rough, mountainous tract of land that existed between the city of Jerusalem and the Dead Sea (see Matthew 3:1 - 12). When he became an adult, he continued to live in the wilderness (Luke 1:80). His clothing was rough, and his diet was strict (Matthew 3:4, Mark 1:6).
God called John to prepare the people for Jesus' teaching and ministry. His ministry began when he was 30 years old (26 A.D.) and started to diminish when Christ's ministry began. He was put in prison by Herod Antipas for speaking out against his marriage to his sister-in-law Herodias.
Jesus stated that not only did John fulfill prophecy he also (although the Bible records not one miracle he performed) was the greatest prophet sent by the Father (Matthew 11:7 - 11).
Interestingly, even though Christ called him the greatest prophet, the Bible does not record him performing a single miracle (e.g. healing the sick, etc.). He was ultimately beheaded, during a celebration of Herod's birthday, in the spring of 29 A.D. (just before the Passover).
Immediately after Jesus' transfiguration, in the presence of three of his disciples, they asked Him about Elijah. They wanted to know why the scribes said he must appear before the end of the world. Jesus told them, "Elijah shall indeed come first and restore all things. But I tell you that Elijah has already come . . ." (Matthew 17:12). The disciples understood that he was referring to the life and ministry of John the Baptist (verse 13).