With the predominance of orthodox Christianity, it can be easy to overlook the smaller non-conformist churches.
In the 19th century, America was a hot-house of schism among Christians, giving rise to some unique new churches, which spread throughout the world.
After Protestantism in the 14th century and non-conformism in the 17th, Christadelphians, Jehovah's Witnesses and Christian Scientists all created their churches in the rising turmoil of the 19th century.
London-born doctor and bible student John Thomas, too modest to lead "Thomasites", bade his followers call themselves Christadelphians, "Brothers in Christ". They succeeded in persuading the authorities North and South that they were conscientious objectors to the American Civil War, as they have been since.
In 1881, Charles Taze Russell founded the Zion Watchtower Tract Society, in expectation of "the time of the end", beginning what was to become today's Jehovah's Witnesses.
In 1866, Mary Baker Eddy, after recovering from serious illness through prayer, founded the Church of Christ, Scientist, with an emphasis on faith-healing, in her book Science and Health.
In the UK, there are 135 Christian Science churches, 125,000 Jehovah's Witnesses, and the Christadelphians have Ecclesias in most of the major cities. The children of these and other non-conformist Christians carry a heavy burden of conscience, expecting to confront a wider society that does not share their beliefs. And expectations of them by their parents are high.
Non-conformists challenge the religious attitudes of mainstream Christianity, such as the question of whether Christ is God, the concept of an afterlife, or the existence of the Devil. They have also challenged secular authority, as conscientious objectors in war, and refusing to pledge allegiance to the American flag, as the Witnesses did.
Teacher and youth worker Darren Storey, explains that Christadelphians want their children to be chaste, and avoid the idolatry of the celebrity culture. The major Ecclesias have Sunday schools and youth clubs, which mix bible study and games.
Spokesman Tony Brace explains that Jehovah's Witnesses are not prejudiced against homosexuals or promiscuous people, but their beliefs "preclude promiscuity and homosexuality". Teachers can challenge these views but have to accept that these children do not accept what they are told as the gospel truth.
Christian Scientists and Witnesses have attitudes to health that could cause misunderstandings at school. On biblical authority, Witnesses reject blood transfusions. They understand the legal "principle of necessity", under which doctors treat people incapable of making informed choices, as do Christian Scientists, who have a broader objection to medical science.
Tony Lobl of the Christian Science Committee explains that "we feel prayer is more effective", and children with a headache might get more out of a little quiet time than being sent to the office for an aspirin.
Surprisingly, perhaps, it is not religious education that makes problems for these children; most appreciate the comparative religions approach, even welcoming the lesson that other people have different views.
Assemblies might pose a problem, typically prayers or hymns that assume the Trinity. But for Christian Scientists, biology lessons might, since even exposure to medical theory, they say, can undermine the efficacy of healing prayer.
Followers of all three faiths say it is ultimately a matter for families to decide whether to withdraw children from lessons, though they all prefer not to do so. They are also reluctant to single out their children or make them feel different. But do not be surprised if a Witness child does not celebrate birthdays, or Christmas. "It is the old Roman Saturnalia," Mr Brace says, "and the only birthdays celebrated in the Bible were Herod's and the Pharoah's."
Jehovah's Witnesses and Christadelphians reject the Trinity (God the father, God the Son and God the Holy Ghost). Christ is not God, but the Son of God.
For Jehovah's Witnesses and Christadelphians, the Bible is the literal word of God, though for Christian Scientists, it has a literary and allegorical character, too.
Christadelphians and Jehovah's Witnesses believe that death is the end of life. Both believe in the resurrection, when the dead will be brought back to life. For Jehovah's Witnesses, all of those who side with Jesus will live in Heaven on Earth, but a select group of followers, exactly 144,000, will rule alongside Jesus in Heaven. Christian Scientists aim to abolish death in their thoughts, and this is the route to eternal life.
All three churches place freedom of conscience at the centre of their teaching. Evil in the world is man's failure, not God's, because man has the ability to choose between good and evil. For the Christadelphians, that means there is no devil tempting us.
For Christian Scientists, healing through prayer is not spiritual alone, but physical healing, too. Healing is the proof of Christianity, hence Christian Science.
All three churches teach chastity before marriage, and moderation, if not outright opposition to drinking.
Christadelphians and Jehovah's Witnesses follow civil authority where they can, but insist that God's law takes precedence, and will not take up arms or idolise flags.
Church of Christ, Scientist Churches and reading rooms can be found at: www.cschurches.co.uk. The Christian Science Monitor is a respected news outlet: www.csmonitor.com
The Jehovah's Witnesses can be contacted at The Watchtower Society, IBSA House, The Ridgeway, London NW7 1RN, where you can get a copy of Jehovah's Witnesses and Education. The Watchtower: www.watchtower.org
Christadelphian Ecclesias are well-represented on the internet, and you can find contact details for most of Britain's major towns and cities by following the links in this directory: www.christadelphian.org.ukdirectoryRegionalUK