I would definitely agree with Ruth that a software engineer is a real engineer for the reasons that she gives. I do recognise though that a lot of software engineers don't class themselves as engineers (I trained as a softare engineer though I am now an Enterprise Architect).
I like Ruth's view and would extend it - its being able to see and use the principles even though the domain in which they come from might not be the same as yours.
I have always thought of the (professional) engineer as someone who solves practical problems through the application of sound scientific/mathematical principles.
So by that token a Software Engineer is just as much a 'real' engineer as any other branch; the tools used in each branch may be different, but that doesn't make them less valid! Just as in any other field, you are not working within a vacuum and need to consider wider aspects. It is no good creating the next best app, if it takes a super-computer to run it!
But on a serious note I have been giving talks to children as part of the STEM ambassador programme and I explain engineering as the use of science to make things.
