A study has found that cell phones cause infertility, is this something to worry about or is the study flawed?
The study is basically worthless.
First, the study was not constructed to test this hypothesis, so it's just something interesting that may point to future studies. It does not provide sufficient evidence.
But the biggest problem is that the study was of 52 individuals with only one or two samples, which makes it statistically useless.
Any uncontrolled variable could account for all the difference detected. If one person had low sperm count because they wore tight underwear it would completely account for the difference.
This would barely qualify as an exploratory study, much less anything conclusive. This study would need to be reconstructed with a minimum of thousands of people, or control the participants' behavior (preferably both), to produce useful conclusions.
Any study with a really small N that deals with human behavior is basically worthless as far as any certainty goes.
The questionnaire is not any better — cellphone position is just binary: 1 belt and/or pocket, 2 anything else. Since most of the people are going to fall in the first category, there are very few degrees of freedom to work with. They just ran all the numbers hoping to get something. This is barn door statistics at its worst.