Although the prospect of miracle cures from therapeutic cloning has been used to sell California voters on a US$3 billion stem cell research institute, one of the world’s leading stem cell scientists says that it will not work. “The so-called therapeutic cloning to my mind is a non-event,” Professor Alan Trounson, of Monash University in Melbourne, told Nature Medicine. As a method for developing therapies, “it’s just not realistic.”

What has discouraged Trounson and other researchers about the highly-touted method of creating personalised therapies using embryonic stem cells is the quantity of human eggs required. “There’s got to be a better way,” says Jose Cibelli, of Michigan State University. “I can predict that therapeutic cloning is going to be obsolete.”

However, the ethical issues have not vanished. Researchers are now working on equally contentious producing embryonic stem cells. A feature in Nature Medicine describes three of these: getting mature cells to revert to an embryonic state; creating hybrid clones with animal eggs; and creating artificial eggs and sperm from which embryos can be produced.