The husband and wife from Berkshire applied for funding for IVF in June, after three years trying unsuccessfully to start a family.
NHS Berkshire East Primary Care trust (PCT) refused to pay, because the woman, aged 37, was too old to meet their criteria - which is to only fund treatment for women between the ages of 30 and 34.
The case is thought to be the first attempt to sue the Health Secretary directly over decisions about NHS rationing, and the first time that age discrimination laws have been used to fight for fertility treatment.
Although national guidelines say women should be funded for treatment up to the age of 39, local PCTs can set their own restrictions, leaving a postcode lottery across the country.
The couple have twice appealed to the PCT, which has refused them funding but has said it will review its policy, in the light of new age discrimination laws which mean healthcare should not be denied on grounds of age.
However, the organisation is due to be abolished in an NHS restructuring in April, and the couple fears the decision will be left to its successors, and that any assistance will come too late.
As a result, they have launched a landmark legal case against Jeremy Hunt, the Health Secretary, on the grounds that he is ultimately accountable for healthcare in England.
Legal documents have been sent to Mr Hunt, as well as the PCT, setting out the intention to issue judicial review proceedings.
The couple, described in legal documents as Mr and Mrs K, went to their GP in June, after three years attempting to conceive. Investigations established that Mrs K had no fertility problems, but that her husband was sub-fertile.
Nevertheless, Mrs K's age was the reason why Berkshire East PCT refused to fund IVF treatment, and rejected subsequent apppeals.
The PCT will only fund treatment for women who are between the ages of 30 and 34 and have already spent at least three years trying to conceive.
The couple have now taken out a loan to pay for private treatment, while they wait to see whether the courts allow a judicial review to go ahead.
Under age discrimination legislation which came into force in October, the NHS is open to legal action from any patient who can demonstrate that they were denied health treatment because of their age.
It means older patients could sue if they are refused hip operations, cancer surgery and other treatments simply because of age.
When the law came in, Norman Lamb, a health minister, said the changes could open the heath service up to claims by those who were denied IVF because of their age.
He said: "If an older woman sought to argue she should have access to treatment on the NHS she can challenge it, but she would have to show that the upper age limit was not objectively justified.
"What I'd say generally is that if people in any condition feel that a judgment can't be justified, and feels arbitrary, then they should challenge it because we should always be making our judgment in the health service on clinical need."
The rationing body the National Institute for Health and Clinical Excellence (NICE) has re-written its guidelines on fertility treatment in a bid to ensure the health service complies with the laws.
Currently, NICE says woman should be funded for three cycles of IVF treatment if they are aged between 23 and 39.
Its draft recommendations go further, to say women should be funded for some fertility treatment up to the age of 42.
Few PCTs meet the current guidelines, with many offering fewer than three cycles of treatment, or limiting the age criteria.
In NHS North Yorkshire and York, women were told in 2009 that they could only qualify if they were aged between 39 and a half and 40. Now the PCT is one of a handful to fund no IVF treatment, unless cases are judged "exceptional".
In Shropshire, a woman was refused fertility treatment because her husband had children from a previous relationship.
Clare Lewis-Jones, chief executive of patient charity Infertility Network UK said too many PCTs had drawn up arbitrary rules, which left infertile couples facing long battles to have any hope of securing NHS funding.
She said: "IVF funding should be available where it is most likely to benefit people trying to have a baby – which is precisely why we have the NICE guidelines.
"However, as many PCTs choose to simply ignore these guidelines and instead put in place their own, arbitrary selection criteria, couples have to fight for the treatment they are entitled to. If Berkshire East PCT did what they were meant to do, this couple would not be in this unenviable situation today."
In April, 151 PCTs will be abolished and replaced by 212 Clinical Commissioning Groups, under the Government's health reforms. The new bodies will remain free to set their own restrictions on funding.
A spokesman for NHS Berkshire East PCT said: "We can confirm that our solicitors are in receipt of a letter relating to this case and we are in the process of considering its contents.
"It would be inappropriate for the PCT to comment further in advance of responding directly to the patient's solicitors."
A Department of Health spokesman said decisions were taken locally and that PCTs and the CCGs which replace them should "have regard" to the national recommendations made by NICE.
Article from The Telegraph