Couples who want legal recognition of humanist marriages have faced family difficulties and "extremely distressing" times, the High Court in London has heard.
Six couples are bringing legal action against the Government over rules which mean humanist marriage ceremonies in England and Wales are not legally valid.
As the landmark challenge kicked off in a remote Skype hearing yesterday, the couples argued they are being unlawfully discriminated against due to their beliefs and do not want "a civil marriage with humanist 'bells on'".
They include Carrickfergus couple Jenny McCalmont and Finbar Graham, both 46.
They plan to marry on July 31 in a humanist ceremony at a beach in Devon where they first holidayed together and where Jenny's parents live. Humanist weddings, involving a non-religious ceremony, are legal in Northern Ireland and Scotland but are still not considered official in either England or Wales.
Caoilfhionn Gallagher QC, lead counsel for the claimants, said they were listening to the hearing "eagerly" from around the country. She said that all the couples wish, or would have wished for those who are already married, to have "legally binding humanist marriages" in England.
"But they have been prevented from marrying in the way that they wish and in accordance with their beliefs as a result of the operation of English law.
"It's a matter of profound concern to all 12 claimants, and for some of the claimants it's been extremely distressing and has caused very particular personal and family difficulties," Ms Gallagher said.
She pointed out the importance of a wedding day for the six couples, and made reference to the Law Commission's scoping paper "Getting Married".
She read a section which said: "A couple's wedding day is one of profound emotional, cultural, social and legal significance.
"It is often presented as the best or most important day of one's life, and as a result is generally seen as requiring a special level of celebration and expenditure, both by the couple and by family and friends."
Court papers say the claimants want to have an "explicitly humanist form of marriage", adding: "They do not want a civil marriage with humanist 'bells on'."
The document goes on: "Legal recognition/validity (of humanist marriage) is also important to the claimants because it signifies that the state recognises that their deeply held beliefs, and the cause of humanism, are legitimate and worthy of recognition and respect on an equal footing with religious people.
"Marriage, for the claimants, is a profoundly humanist event reflecting a right to marry and the universal human values of love, fidelity, trust, sharing and co-operation.
"They believe that this is the one life they will ever have. In that context, the decision to marry, for humanists, takes on an even more profound significance."
The challenge, which is being heard by Mrs Justice Eady, is being opposed by the Government.
The couples are being supported in their action by Humanists UK, which has been campaigning on the issue for some years.
Humanists UK president Alice Roberts said: "A humanist marriage is something so incredibly special - a ceremony where the couple decides on the meanings, beliefs and values they feel important - rather than having to shoehorn themselves into some other template that society is forcing on them. It represents that freedom of belief that is a fundamental human right.
"I find it so extraordinary that while humanist marriages are legally recognised in Scotland and Northern Ireland, they're not in England and Wales. This is about human rights."
As humanist ceremonies are not recognised in law in England and Wales, couples with humanist beliefs must also have a civil ceremony.
A Ministry of Justice spokesman said: "We want to give couples more choice in how they celebrate their commitment to each other. That is why we asked the Law Commission to review marriage and make recommendations for a simple, fair and consistent system for all."
The hearing is expected to last two days.