The prepared sperm is used to inseminate the eggs by leaving them together in culture dish that mimics the natural environment. If the sperm quality is good, then approximately 50,000~100,000 sperms are placed together with the egg. However, if the quality of the sperm is poor (low motility, low count, etc.) additional method called ‘intracytoplasmic sperm injection’ (ICSI), when a single sperm is injected into the egg, will then be performed to aid in fertilization.