Scientists have launched a project which aims to find ways of making bones from blood.
Two million litres of cord blood are currently banked across Europe
Researchers at York University hope to create bone structures from umbilical cord blood stem cells for use in the repair of bone defects and fractures.
The three-year project costs £1.6m and is backed by the European Commission.
It hopes to find a viable new use for the two million units of cord blood banked in Europe and currently used for transfusions and treating leukaemia.
Biologist Dr Paul Genever, who is co-ordinating the project, said: "Stem cells in cord blood appear similar to bone marrow stem cells but they are hard to locate. We aim to isolate and expand them so we have enough cells to use in therapies.
"We also want to compare them with bone marrow and embryonic stem cells and investigate how we can turn them into bone structures for use as 3D bone replacements."
He said if the creation of bone structures from stem cells proved viable, it might be used for cell-based therapies to repair bone defects and fractures.
Ultimately, bone structures developed in this way could be used to make hip replacements more durable.
Dr Stephen Holland and Professor Tom Baldwin, from the university's Department of Philosophy, will carry out an ethical evaluation of the research to assess how it contributes to the debate about the ethics of stem cell research.