Would you, could you or should you donate your body to science? That might be a hard enough question to answer but what about donating your children's tissue to research after their death. This is exactly the situation Sarah Gray and her husband found themselves in when one of their twins, Thomas, died.

Thomas, was born with anencephaly and died 6 days after birth. Sarah and her husband donated Thomas's tissues for scientific research. With time Sarah's desire to know what Thomas's tissue has been used for got the better of her. She went on an extraordinary journey to understand the full extent of Thomas's legacy, visiting the institutions which had received parts of his liver and eyes and tracing the scientific impact of his donation.

Joanne Mullarky is a research nurse at the University of Bradford's Human Tissue Bank. When she heard Sarah's story she changed the way she worked and now today thinks that a stronger relationship between academic institutions and donor parents is vital to increasing the amount of tissue donated. Tissue that is currently rarely donated.

A Brainwaves special recorded in front a live audience at the Edinburgh International Book Festival. Honest, thought provoking and profoundly moving, Sarah's story of Thomas's donation will question the way we think about life after death and the extraordinary gift of giving a dead body to science.