The review's authors chided gene therapists for promising too much and delivering too little.

For example, to get a gene into the brain, gene therapists are using a modified herpes virus that has a predilection for nervous system tissue.

To get corrective genes into cells, gene therapists have to rely on viruses, which specialize in exactly this task.

Well before Mr. Gelsinger's death, gene therapists had been trying to develop more suitable viruses as vectors.

Dr. Crystal, himself a gene therapist who works on cystic fibrosis and heart disease, is diffident about the hair restoration question.

The ultimate goal of gene therapists is gene replacement, which would totally alter the fate of people born with genetic diseases like cystic fibrosis, diabetes and hemophilia.

Will victory go to the person with the best drugs and gene therapists?

The vector is the disabled virus used by gene therapists to insert corrective genes into human cells.

The HIV retrovirus really shook us up because it's so lethal, but the cloned retroviruses the gene therapists use are harmless.

If they were right, the immunosuppressive drugs could turn out to be nature's gift to gene therapists, Dr. Crabtree said.