Dakoka received millions of stem cells injected into her head
For Wilma Clarke, there is no doubt. Her three-year-old daughter, Dakota, born with a rare condition that left her almost blind and suffering from balance problems, can see things that she could not see before.
"I know she is seeing because she is a completely different child," Mrs Clarke told BBC's Panorama.
Dakota's parents say her improvement is down to controversial stem cell treatment that she underwent in February - at a cost of £30,000 - at the Beike Biotech clinic in Qingdao, northeast China.
The family, from Newtownabbey in Northern Ireland, tapped into their savings and raised the £20,000 cost of the treatment, plus their travel expenses, in a series of local fundraisers.
The Clarkes are among a growing number of what scientists term "stem cell tourists", people looking abroad for therapy which - with rare exceptions - is not licensed for use in the UK.
Its effectiveness is questioned by mainstream scientists, who worry that desperate families are taking risks and spending vast sums on treatments that are years, possibly decades, away from being successfully developed.
"If these were reputable cell therapies, why do you have to go to the Dominican Republic, why do you have to go to Russia, why do you have to go to China? Why can't you have those therapies in the UK?" said Dr Stephen Minger, a stem cell expert at King's College London.
The arrival of President Barack Obama in the White House threw stem cells back into the headlines as he loosened controls on US government funding for research that uses stem cells from aborted foetuses.
Experts say media reports boasting of 'miracle cures' are dangerous
Scientists universally agree that the cells, which have the capacity to repair damaged tissue, nerves and even rebuild organs, hold massive potential in treating an array of illnesses, including Parkinson's disease and Alzheimer's.
But, they say, while the research being carried out shows great promise, much more needs to be done.
Early results need to be retested, clinically trialled, peer reviewed and published in reputable journals before they can apply to have the therapies approved by regulators.
It is, they concede, slow work.
Dakota was born with septo-optic dysplasia, in which part of her brain and her optic nerve did not develop - a condition that affects one in 50,000 children born in the UK each year.
STEM CELL MILESTONES
1960s: Research begins on stem cells taken from adult tissue
1968: Adult stem cells used to treat immunodeficient patient
1998: US scientists grow stem cells from human embryos and germ cells, establishing cell lines still in use today
2001: Embryonic stem cell turned into a blood cell
2002: UK regulator issues two licences to begin research on embryonic stem cells
Despite the advice of doctors to avoid scouring the internet for so-called 'miracle cures', the Clarkes said they did exactly that and read the testimonials of other parents who had been to China for stem cells.
In China, Dakota received six injections into her head over the course of a month.
Upon her return, the Clarkes agreed to allow doctors in Belfast to carry out extensive tests on her vision. Those tests concluded that there was no improvement.
Yet her parents remain convinced that she is improved.
"If a specialist wants to argue the point... come and watch my child and tell me that the child isn't seeing anything and that [it] never made a difference," said Darren Clarke, Dakota's father.
"We know our daughter better than anybody else and we know there's been a change in her," said Wilma Clarke.
Dr Xiang (Sean) Hu, chairman of Beike Biotech, told Panorama that western scientists who travel to his clinic to learn about their techniques go home impressed.
"I get many English professors and doctors coming to visit us, or American doctors after they talk to our patients they start to [say] 'congratulations, you guys are doing something great'."
He said the vision tests carried out on Dakota in Northern Ireland are not conclusive.
Dr Larry Tychsen from the St Louis Children's Hospital, told Panorama that his examinations in the US of former patients of the Beike clinic also showed no improvement, but that parents did not seem to want to know if there was 'actual' improvement.
"You can understand from the standpoint of the parent, they have invested a tremendous amount of time and money in this. The expectations are high and they are not sure that they want to know that you think they have wasted their time and money."
Panorama: Stem Cells and Miracles, BBC One, Monday, 18 May at 2030 BST.