Got Milk?

And here is a post from another student that needs some work.

 After learning of the many ways in which an expirimental design can deliver inacurate results, I have become skeptical of many scientific claims. Some of the errors in scientific studies include participants not being selected randomly, biases of the researcher and not ruling out rival hypothesis. Causation vs. correlation, random selection and pseudoscience all cross my mind when hearing results of a correlation or experimental design. I am now skeptical of one very popular and strongly believed in theory: Milk builds stronger bones.


http://t2.gstatic.com/images?q=tbn:ANd9GcQXIr9u3WwIuPAc9mS8YX1zgMYZFDMBKYM2tJqrA_lid5EdbDk9
Many new studies bear results that contradict the common belief that milk makes your bones stronger. Some studies show milk drinkers to have stronger bones than non-milk drinkers, some studies yield the opposite, while some studies show no relation between milk and bone strength. How can there be so many different, contradicting results?
I believe many of these studies aren't selecting their subjects randomly. If you compare children that eat well, live a healthy life style and drink milk to children that lack milk in their diet and live an unhealthy lifestyle, the milk drinkers may have stronger bones and it won't necessarily be due to the fact that they have more milk in their diet. Another flaw in studies on the effects of milk may simply be a matter of correlation versus causation. There are researchers that claim drinking milk causes osteoporosis. "Evidence" of this claim is that the United States, with the highest consumption of dairy, has the highest rates of osteoporosis. This relationship may be due to one or more other variables such as: diet, exercise, and BMI (body mass index). The claim that milk builds stronger bones needs to be further researched and scientifically tested before I depend on milk as my source of calcium.

Links to studies on milk's effects: http://www.livestrong.com/article/315144-does-milk-build-strong-bones/ http://www.whymilk.com/strong_bones.php http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/calcium-and-milk/
After seeing all of the research that suggests such a popular theory as this may be somewhat, if not completely, incorrect, I am forced to wonder: what other mainstream theories that I believe be true could actually be false?