Although it is not known for a fact, a conjecture is that John the Baptist was orphaned because his parents were old. He was taken in by Jewish monks called Essene who lived apart and in the wilderness. Evidence of this is the way that John is described in The Bible, from the wild, in goat hair clothes and living off the land. All of these are representative of the Essene. Essene are one of four parts of the Jewish faith.
We do not know what sect or group John the Baptist may have belonged to, but some believe that the gospel description of his clothes, lifestyle and teachings are reminiscent of the Essene sect of Judaism.
Zacharias was of the tribe of Levi, more specifically a descendant of Aaron through another descendant, Abijah. Only male descendants of Aaron could serve as priests - see Exodus 28:1. John's mother was also descendant from Aaron:
Luke 1:5New King James Version (NKJV)
John's Birth Announced to Zacharias5 There was in the days of Herod, the king of Judea, a certain priest named Zacharias, of the division of Abijah. His wife was of the daughters of Aaron, and her name wasElizabeth.
John would have been from the tribe of Levi.
He was not apart of a religious group. Look up Anabaptist.
that it was incredible
His father was a priest and his mom was a household mother:Luke 1:5New International Version (NIV)The Birth of John the Baptist Foretold5 In the time of Herod king of Judea there was a priest named Zechariah, who belonged to the priestly division of Abijah; his wife Elizabeth was also a descendant of Aaron.
He was a doctor who belonged to a vegetarian group
The Gospel of Luke begins with the birth of John the Baptist.
St. John the Baptist
There is no Bible evidence to support the idea that John the Baptist had any siblings. Elizabeth, his mother was already an aged women when she miraculously became pregnant and gave birth to John her first born.
Essenes
Yes, according to Christian tradition, Saint Elizabeth, the mother of John the Baptist, gave birth to him in her old age as she was previously thought to be barren.
6 months
Actually, we do not know the date of the birth of John the Baptist nor of the birth date of Jesus. However, the Church chose to celebrate the birth of Jesus on December 25. John, according to scripture, was about 6 months older than Jesus so he was given the date of June 24.
The Nativity of John the Baptist on June 24 commemorates his birthday - six months before that of Our Lord.
John the Baptist, just like all Jewish boys, was circumcised and named on the 8th day after his birth.