I know it's been done in mice but I don't know how efficiently, although these days the main way you transform mouse germline DNA has been doing low-efficiency transformation and selection of embryonic stem cells in culture followed by 2 generations of mucking around making chimeric embryos from those stem cells and breeding the resulting animals so this definitely saves time if it works well.
If you can do it in one generation that also means that you can start doing it in humans embryos.
For legal reasons probably not in the West, but I can imagine that the Chinese are willing.
I've been hearing around the news about a new genetic engineering method called CRISPR. The method can purportedly edit any gene in a human genome (or other animal or bacterium genome) with very high accuracy. The new method may remove the risks associated with gene therapy, which can introduce undesired mutations by inserting genes into the middle of an existing gene sequence.
Here's a report:
http://www.independent.co.uk/voices/comment/this-is-a-triumph-of-basic-science-with-huge-implications-crispr-technique-breaks-the-mould-8925323.html
Thoughts? There is already discussion about the use of CRISPR with IVF (in-vitro fertilization) for the purposes of germ-line engineering, but even without this the method may prove very efficacious for gene therapy on non-germ-line cells. What are the ramifications for human engineering? For germ-line intelligence enhancement?