A man’s poor sleep schedule could actually be the reason why some couples struggle to conceive, suggests new research, which is still under review but was recently presented at the American Society for Reproductive Medicine’s annual conference in Salt Lake City.

A good night’s sleep, according to the research, means no less than six hours and no more than eight. So all that catching up you do on the weekends isn’t entirely beneficial either. Through examining previous data on 695 couples, the researchers found that the quality and length of men’s sleep is associated with their chances of successful conception. Men who regularly slept less than six hours or nine plus were 42 percent less likely to impregnate their partners within a given month compared to those who got eight solid hours of Zs. Guys who reported some trouble sleeping were also less likely.

This is because a healthy sleep cycle regulates daily testosterone levels, which, in turn, promotes sperm concentration, count and overall quality. Disclaimer: This is by no means meant to encourage you to skip or, maybe worse, speed up sexy time before bed. Just use your time wisely, fellas.