Long time since I posted, My biggest worry with the technology...

Long time since I posted,
My biggest worry with the technology is the competition from CRISPR, a more powerful method of gene editing.  As we see from the first experiments on human cells, there is a long way to go before this is ready for the clinic, and the same sort of preclinical hurdles ddRNAi faced and overcame are only just starting to be tackled.  These hurdles are a long way from being overcome, so competition from CRISPR is many years, perhaps even decades away.

From http://www.nature.com/news/chinese-scientists-genetically-modify-human-embryos-1.17378

Nature | News
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Chinese scientists genetically modify human embryos

Rumours of germline modification prove true — and look set to reignite an ethical debate.

• David Cyranoski
• & Sara Reardon

22 April 2015
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Dr. Yorgos Nikas/SPL
Human embryos are at the centre of a debate over the ethics of gene editing.
In a world first, Chinese scientists have reported editing the genomes of human embryos. The results are published1 in the online journal Protein & Cell and confirm widespread rumours that such experiments had been conducted — rumours that sparked a high-profile debate last month2, 3 about the ethical implications of such work.
In the paper, researchers led by Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou, tried to head off such concerns by using 'non-viable' embryos, which cannot result in a live birth, that were obtained from local fertility clinics. The team attempted to modify the gene responsible for β-thalassaemia, a potentially fatal blood disorder, using a gene-editing technique known as CRISPR/Cas9. The researchers say that their results reveal serious obstacles to using the method in medical applications.
"I believe this is the first report of CRISPR/Cas9 applied to human pre-implantation embryos and as such the study is a landmark, as well as a cautionary tale," says George Daley, a stem-cell biologist at Harvard Medical School in Boston, Massachusetts. "Their study should be a stern warning to any practitioner who thinks the technology is ready for testing to eradicate disease genes."