The study looked at the semen quality of 16,835 infertile men in China compared to 1,567 sperm donors. They found that infertile men mainly had issues with weak sperm movement. Azoospermia, asthenospermia, and oligoasthenospermia were more common in infertile men, while oligozoospermia was less common. Azoospermia, asthenospermia, and oligoasthenospermia are linked to infertility, but just having low sperm count may not be.