Experts celebrating the 25th anniversary of the first IVF baby say advances in the next decade will give everyone a chance of parenthood.
IVF techniques are constantly advancing
Leading fertility doctors from around the world, in London for a conference marking the occasion, said that eventually, no-one would be beyond help.
At present, the majority of men and women with fertility problems have a chance to become parents using techniques developed in the last 30 years.
However, there are some - for example those who cannot produce their own eggs or sperm, and have none in storage - to whom doctors cannot offer any assistance.
Professor Alan Trounson, from one of the world's leading research clinics, based in Australia, said that progress was being made towards a solution.
"I am certain that in the long term we will be able to help everyone," he said.
"In future we'll be able to take cells and reconstruct the equivalent of sperm and eggs. It is theoretically possible."
More research needed
He said that much more research involving "stem cells" taken from "surplus" IVF embryos would be needed to reach that goal.
Some experiments are already underway in mice with limited practical success so far, although experts say that much more is understood about how eggs and sperm might be constructed.
Professor Trounson said that the breakthrough was not imminent - predicting at least a decade's delay before an egg or sperm could be made.
The use of embryonic stem cells for research purposes is permitted in the UK, but remains controversial.
Message from pioneer
Since the birth of the first IVF baby, Louise Brown, at 11.47pm on July 25, 1978, in Oldham, there have been well over a million "test tube babies" born worldwide.
Professor Robert Edwards, who, alongside Mr Patrick Steptoe, led the pioneering team that produced Louise, said
Professor Edwards, 77, said: "Louise's birth signified so much; for the first time science and
medicine had entered human conception in a most decisive manner."
Louise Brown moments after her birth in 1978
He said that research connected with IVF had yielded the opportunity to correct or even treat serious genetic diseases in future.
He said: "My
only regret is that Patrick Steptoe is not with us today since that
partnership, though somewhat difficult at times - showed that these two
disciplines could work together to offer the best of each."
He added: "May I express my sympathy to those IVF patients who have
tried but failed.
"We have reduced the proportion who fail but we
must continue to improve on it.
"Let us now celebrate what must be
now approaching 1.5 million IVF babies born distributed amongst
almost every country of the world."