Many people are denied infertility treatment on the NHS, fuelling calls for more government funding.
According to Infertility Network UK, women face restrictions based on their age, size, and whether or not they already have children from a previous relationship.
Spokeswoman Susan Seenan commented: "In 2004, Nice (the National Institute for Health and Clinical Excellence) said as part of their fertility guidance that it should be the case that any woman between 23 and 39 who has a proven cause of infertility, or infertility of three years duration, should have access to three cycles of treatment on the NHS and that should include frozen embryo transfer.
"We're now nearly in 2008 and what is actually happening is that some PCTs (primary care trusts) are offering one cycle, some are offering two and very, very few are offering three."
Ms Seenan revealed that some PCTs offer infertility treatment at the start of the financial year and then run out of money after a couple of months so that they are unable to provide more.
"Basically it's a real postcode lottery and it's a very, very unfair one," she added.