The parents of the world's first IVF baby - born 40 years ago next week - would not have got the procedure on the NHS in most of England today because of "social rationing", a charity has said.
NHS IVF is unavailable to couples in many areas if either of them has children from a previous relationship.
One mother said not meeting such criteria was "crippling".
Fertility Network UK said action was needed to keep fertility treatment available for all.
NHS England said it has "never been able to offer all of the IVF that people might want" and the Department of Health and Social Care added "funding for the treatment has increased".
Figures collated by campaign group Fertility Fairness show IVF provision at all 208 clinical commissioning groups (CCGs) across England.
They show eight out of 10 CCGs do not enable access to IVF if one of the couple has children from a previous relationship.
Next Wednesday marks the 40th birthday of the world's first "test tube baby", Louise Brown.
Her father already had children from a previous relationship, which would render the treatment unavailable to the couple in many areas today, Fertility Network UK said.
Aileen Feeney, chief executive of the charity, said: "If Louise Brown's parents wanted to try NHS IVF today, they would be turned down by the vast majority of England's clinical commissioning groups on social rationing grounds: although Mrs Brown was clinically infertile, Mr Brown had a child from a previous relationship.
"England pioneered the development of IVF but that achievement means far less if the people who benefit from this amazing, life-creating technology are determined by their postcode or pay packet. Fertility Network urges the government to take action now - or we are creating a society where only the more affluent will have access to IVF."
Sarah Dean's fertility issues started after she had cervical cancer aged 25. She had an operation to remove her cervix in 2011.
The 32-year-old and her husband Paul, from Sutton Coldfield, decided to undergo IVF treatment, but were refused treatment on the NHS as Paul had children with a previous partner.
"The NHS have been amazing for everything that I've had done for me but when it came to IVF being the next step, for them to then look at the eligibility and having children in the family, it was really disheartening," added Sarah, who gave birth to son George in May following two cycles of IVF.
"I had been through so much to then be told because there's already children in your family you're not eligible. That was crippling because you then have to look into what are our options, it was really difficult.
"The challenge of reasoning with how can they make that decision was difficult."
In England, four CCGs out of 208 offer three full IVF cycles for women under 40, including access for couples with children from previous relationships.
All of those are based in the Greater Manchester area, including Oldham CCG - where Louise Brown was born.
Seven CCGs offer no IVF treatment on the NHS, including Cambridgeshire, Mid-Essex and South Norfolk CCGs.
North East Hampshire and Farnham has two different policies, with one cycle offered to people in north-east Hampshire and two to couples in Farnham.
The National Institute for Health and Care Excellence (NICE) issued guidelines in 2004 that stated women under 40 who had failed to get pregnant after two years of trying should be offered three full cycles of IVF on the NHS.
However, the recommendations are not binding and it is up to local NHS providers to decide what to offer.
An NHS England spokesperson said: "In reality the NHS has never been able to offer all of the IVF that people might want, nonetheless, the number of cycles funded by the NHS in England remain consistent.
"Improving birth rates and expanding treatment options mean more people than ever are successfully starting a family."
A Department of Health and Social Care spokesperson said: "We are increasing funding for the NHS by an average 3.4% per year.
"The government has been clear that IVF services should be accessible to patients that meet the criteria set out in NICE guidance."