Obese fertile men appear to have reduced testicular function. Whether this is cause or effect, i.e. adiposity impairing spermatogenesis or reduced testicular function promoting fat deposition, remains to be determined.

The present study confirms that participation rates are low in studies of semen quality. Although the expected higher participation of subfertile couples was not confirmed, there remains considerable potential for bias and other problems that could invalidate this type of study.

No abstract