Oligoasthenospermia is a condition affecting male fertility in which the semen of a man has fewer than normal numbers of healthy sperm cells. In addition, the sperm cells that are present often have decreased motility or movement abilities. Oligoasthenospermia can be referred to as oligozoospermia, a general term for sperm with low numbers, or asthenozoospermia, low motility of present sperm. The cause of oligoasthenospermia is often unknown, but there are several factors that may contribute to its development. These include genetic abnormalities, environmental toxins, exposure to certain drugs, radiation and chemicals, sexually transmitted infections, and lifestyle factors such as intense exercise, overheating of the scrotum from hot baths, and obesity. Testing for oligoasthenospermia is often done as part of a semen analysis as part of an infertility evaluation. In these tests, the semen sample is assessed for the number and morphology (shape) of sperm, as well as its motility. If the sperm motility results appear abnormal, a second semen analysis may be ordered to confirm the diagnosis. Treatment for oligoasthenospermia is often dependent on the cause of the disorder. Lifestyle changes, such as abstaining from drug and alcohol use, can improve sperm health; medications and supplements may also be prescribed to improve fertility. In vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI) may also be recommended to help achieve a successful pregnancy.