Young men don't know how supplements affect their ability to conceive.

Alice Newman-Sanders and colleagues from the University of Birmingham and Birmingham Women and Children's NHS Foundation Trust assessed young adults' perceptions of the potential impact of lifestyle factors in the gym and nutritional supplements on male infertility. The analysis included 153 surveys of gym enthusiasts.

The researchers observed statistically significant differences between men's and women's perceptions of the potential effects of some types of active exercise and protein supplements on male reproductive health. Only 14% of participants considered how exercise or supplement use might affect their fertility.

Overall, fewer men thought about their fertility than those who cared about their fertility and thought their fertility was important. Many men are more likely to change their behavior if a particular behavior has a long-term, rather than a short-term, impact on their ability to conceive.

"Men express disturbing concerns about how factors such as exercise supplements may affect their fertility and lead to long-term negative consequences," the authors wrote.