One of the main arguments given against splicing human embryos on there was that embryos couldn't decide for itself whether it wanted it.
I think that's kind of absurd. The decision that impacts it the most has already been made for it - existence. If we take the Buddha's view that life is suffering, then it has been decided that is suffers. Compared to that, what sin is it to give it whatever advantages a few spliced genes can offer?
[1] http://www.radiolab.org/story/antibodies-part-1-crispr/