Abnormal Sperm Counts – Having fewer than 15 million sperm per millilitre of semen is considered an abnormally low sperm count, though higher counts are associated with better fertility.
Poor Sperm Motility – Poor motility occurs when the sperm cannot move forward normally.
Abnormal Morphology – The shape and size of sperm also play an important role in fertility, as at least 4 percent of sperm should have a normal morphology for them to carry out their job correctly.
White Blood Cells in the Semen – Healthy semen should contain no white blood cells but instead consist mostly of seminal fluid and various enzymes and proteins that provide energy for the sperm in its journey toward fertilizing the egg.
Anti-Sperm Antibodies – If a man’s body produces anti-sperm antibodies, these antibodies will attack any invading sperm molecules and thus prevent it from reaching an egg for fertilization.
DNA Fragmentation – DNA fragmentation is caused by either oxidative stress or by genetic damage within individual sperms, causing significant issues with fertility in some cases if there are too many damaged sperms present.