A new study finds another reason for why your sex drive is dwindling, dude – and it's because you want kids. A study published in The Journal of Sexual Medicine this month looked at the psychological and social variables affecting male sexual desire, such as quality of life, sexual function, distress, satisfaction, and psychological symptoms. The number one factor in predicting low sexual desire turned out to be the desire to have a baby. A bit counter intuitive, evolutionarily speaking? Maybe.