Lifestyle advice given by doctors to men diagnosed with infertility should be radically overhauled, says latest research. Current guidelines warn infertile men about the dangers of smoking, alcohol consumption and recreational drug use, as well as the risks of being overweight and wearing tight underwear. However, a team of scientists from the universities of Manchester and Sheffield has found that many common lifestyle choices make little difference to male fertility, based on how many swimming sperm men produce, the journal Human Reproduction reports.