Imagine that we take mirror reflection of a cell - change each molecule into its enantiomers.
In physics it's called parity transform - it's not perfectly conserved, but the differences of energies are many orders of magnitude smaller than thermal noise in biochemistry - such cell should function properly (but for example use L-glucose).
http://wikibin.org/articles/chiral-life-concept.html
We don't have technology to construct such cell in this moment, but maybe in a few dozens of years ...
So I believe it would be wise to discuss about it's possibilities and dangers...
One of the possibility is that such chiral life would be incompatible with most of normal parasites...
What do You think about it?