Asking the question "Is this science really worth pursueing?"

I was going to reply to the Tuskegee post about this, but I felt like this topic deserved its own post. Posting this there would just sidetrack the topic...

So how far do we take science?

A question like this we faced in the 1940's the pursuit of nuclear fission--one result was a potentially awesome power source (though, in my opinion, our government is too stupid to realize it) and another was the atomic bomb.

Another, more recent, example is Hadron. Do we really need to know what makes up subatomic particles if we already know how to work with molecules (chemistry!)?

So now that I presented two examples, where do we draw the line? Can a definite line really be drawn here? I can see this becoming more and more of an issue as our understanding of science grows. Perfect example of a question we now face (or we are going to face.. pretty sure we're facing it now though) is genetic engineering in humans. There are a lot of issues in this topic--like curing genetic disorders, etc etc. But whose to say we stop at genetic disorders? If we can get rid of some cancers, why not get rid of "ugliness" or choose the eye color of kids?

My personal opinion is that science is something we should pursue but theres limits. Like genetic engineering in humans isn't really something we should pursue to the point where we can manipulate genes. Its cruel, but I think genetic risk is a risk we should take. Removing it makes reproducing more of a chore than something special. Instead, we should pursue cures to diseases, injuries and the like. Take for example the (near) science-fiction idea of growing organs. That'd be totally awesome... "Kidneys blew up? Here! Have a new pair, made from your own DNA!"

So how does everyone else feel about this idea? I really didn't touch on "how" as I think there is absolutely no clear-cut answer to this question.