Jump to Causes of low motility - Sperm motility describes the way sperm move. It may affect fertility. Various conditions affecting the testicles may cause poor sperm motility. Drinking too much alcohol, as well as smoking or using recreational drugs, may have a negative impact on sperm motility. Low sperm count is a common fertility problem, but the good news is that getting Sperm motility (their ability to move) and sperm morphology (their form or.