I don't necessarily think the problem is purely because of a lack of intelligence in students today. I agree it is a problem, but why is it that students seem to be lacking in knowledge about science? What I'm trying to say is that this problem is a symptom rather than a cause of a lack of interest in the sciences.
It seems to me that the problems cause stems from an early age. It seems that a lot of students go through elementary school without any sort of interest in the sciences, why is that? Perhaps that is the actual question we should be asking. I mean let's face it -- if you don't like something you're not going to continue to pursue it if you don't have to. If students lack an interest in the sciences what is the motivation to pursue mathematics, or any science for the matter? There is none. Because of this students direct their energy into other pursuits and let's face it: if you don't have a solid foundation in math, or any science then of course you will be perceived as unintelligent when it comes to all of these fields. Basically is a lack of interest early on that causes students to skim over the foundations which only leads to more problems later on in their "educational career".
Students are not being inspired to learn anything pertaining to the sciences. The curriculum tries to encourage the scientific method and rational thought but what scientific ideas are discussed when teaching such things? I don't know what it was like for anyone else but to be honest at least for me science was just not interesting in elementary school. I probably would still had a disinterest in physics if it wasn't for two particular high school teachers I had.
What we need is a reform on the ways we teach science. It needs to be taught in such a way as to stimulate interest in children. We all take too much for granted and in doing so neglect the principles which have been the inspiration for innovation, or worse yet fail to see the ingenuity of the innovations in the first place. We need to come up with a way to make sure that innovation is not looked down upon. I'm not particularly sure how to accomplish such a thing but doing so, I believe, would help to create a genuine interest in the sciences.