From This Week in Education, a study reported at MSNBC shows that students who take a lot of math in high school do better in all college science courses.
Well, of course. Science is math-heavy. It may not be proofs like you'll see with mathematics majors, but science uses equations. Equation after equation after equation. There's no way around it. Scientists develop equations based on observations and then need to use equations for predictions. Perhaps biology isn't quite as math-heavy (I only took biology in high school), but it still uses math.
Another way in which math prepares students for science is logic. Math is like a special case application for logic. This logic can help students understand and apply the scientific method appropriately. Even if students don't like math and feel that they wouldn't use advanced math, this skill teaches one how to think appropriately. Those who denigrate any advance math as useless completely miss this point.
This is why poor mathematics education in public (and possibly private and home) schools today leads to less math and less scientists.