On the other hand, we should probably do some due diligence before deciding to embark on a mosquitocide, just to try and swing the odds in our favour.
I.e. please be completely certain that the GM offspring mating with female individuals will not result in some other side effect...
Because, here's the thing - we do know the implications of letting these mosquitoes live. 100s of thousands of people a year die. Every Year.
If you believe the Monsanto GM corn documentaries, releasing GM into the wild may have bad effects (intended or otherwise) outside the designated population. Plants are obviously not the same as insects, but I would prefer to err on the safe(r) side.
Edit: Also, a known bad is often better than an unknown.
You know what would turn around everyone's attitude in about 7 days flat (probably fewer) - have those hundreds of thousands of people dying a year be white, rich, Americans. Every conceivable solution to wipe out the mosquitos would be developed, and rolled out with zero debate (and I mean zero - there wouldn't be a single naysayer of any merit)
People shooting any GM advance on the same basket as if every change was the same irks me. It's similar to talk about how computer malware is harmful, thus you must never install anything on your PC.
The potential of unforeseen mutations occurring is 100%, GM or no. How do you think species evolve?
That's why I love the idea of being able to genetically modify them to produce only male offspring. It provides a nice, asymptotic curve way of culling the population without dramatically changing their ecosystem overnight
If it works exactly as described, the 'only male offspring' modification should be nice and side-effect-free. But then, evolution is a big-numbers statistical game. Who knows what interesting variations we'll see..