The transplants at the centre of the controversy are tiny clumps of brain
tissue from aborted human fetuses several weeks old. Isolating the correct fetal
tissue is tricky, and each operation requires up to six fetuses, severely
limiting how many patients can be treated.
Fetal cells from pigs
This is controversial, because of the threat of animal viruses spreading to
people. But Diacrin, a company in Charlestown, Massachusetts, has treated 42
Parkinson’s and stroke patients with neural cells from pig fetuses. The
Parkinson’s patients have so far suffered no ill effects, but results from the
largest trial suggest that the…
