Five-year-old Zain Hashmi is playing with the fuzzy top of the microphone, readying himself to speak to a room full of journalists.

There are about 20 cameras flashing madly in front of him, but he is completely unperturbed. "Hello, hello, hello," he yells, running up to them, grinning, his arms swinging playfully.

Moments later he stands still to address reporters at his own press conference. "I am Zain. I am five. I have a broken bone marrow," he begins, more shyly now. "I have 100 blood transfusions. I have lots of medicine. I want to get better. Please help me."

There is a sideways glance to his mother, Shahana, to seek her approval after his speech - the mother who has spent all his life searching the world to keep him alive.

Shahana and Raj Hashmi embarked on a desperate battle to create a "saviour sibling", a baby whose embryo was tissue typed with Zain's - to save him.

Zain's rare blood disorder, beta thalassaemia, means his only hope of an ordinary, healthy lifespan is a bone marrow transplant. He needs blood transfusions every three weeks to stay alive.

It was an issue involving problems of ethics, uncharted legal territory, new reaches of science and dwindling time. In May the appeal court ruled in favour of the screening of embryos to check that another child of theirs did not carry the same defect, thus allowing them to select a child who could help cure Zain.

But more pain has followed. Shahana has miscarried several times following IVF treatment.

Yesterday was her attempt, with the support of a number of foundations, to establish an annual international blood and bone marrow awareness and donation week.

Shahana Hashmi wants to draw attention to the marked lack of ethnic minority and mixed race donors on the UK register and around the world, which could be affecting thousands waiting for donated bone marrow.

"We have been on a very long journey," she said. "We have left no stone unturned. We have met equally remarkable people with heartbreaking stories - these families deserve the right to live."

She said the target of Zain's Bone Marrow Foundation, which she established, was to get 20,000 people from minority ethnic backgrounds to sign up to the bone marrow register within a year. She hoped that would increase to 60,000 within three years.

Fewer than 30% of bone marrow patients find a family member with compatible blood stem cells to donate. The figure is far lower for ethnic minority groups.

"Children of Asian extraction are severely disadvantaged as there are not enough Asian donors on the donor registers," said Monty Duggal, head of paediatric dentistry at the Leeds Dental Institute.

"We must motivate and encourage Asian families to become potential bone marrow donors. This means overcoming many cultural dogmas."

After his press commitments, Zain is even more talkative. "I will be up to 101 blood transfusions this week. Not just 100 any more, 101. They don't hurt that much. It's just needles," he says, grin firmly in place.