- Mild teratozoospermia
- Between 10% and 14% of the sperm have a normal morphology.
- Moderate teratozoospermia
- Only 5-10% of the sperm have an abnormal shape.
- Severe teratozoospermia
- Less than 5% of the sperm have a normal morphology.
It should be noted that this definition has been created using the Kruger's strict criteria, according to which a man has teratozoospermia if over 85% of the sperms present in his ejaculate have an abnormal morphology.