What does a semen analysis tell?
Semen analysis is a test that can help health care providers determine the cause of infertility. Performed on semen ejaculated into a cup, the test provides information about sperm and semen. Here are some of the things the doctor looks for:
Amount and thickness of semen. The typical ejaculate is 2-6 milliliters (mL) of semen, or around a 1/2 teaspoon to 1 teaspoon. Less semen than that may not contain enough sperm to achieve a pregnancy. More semen than that could dilute the concentration of sperm. Semen should be thick to start with and become thinner 10 to 15 minutes after ejaculation. Semen that stays thick may make it difficult for sperm to move.
Sperm concentration. Also called sperm density, this is the number of sperm in millions per milliliter (mL) of semen. Twenty million or more sperm per mL is considered normal.
Sperm motility. This is the percentage of sperm in a sample that are moving as well as an assessment of their movement. One hour after ejaculation, at least 50% of sperm should be moving forward in a straight line.
Morphology. This is an analysis of the sperm size, shape, and appearance. The test analyzes 200 sperm, noting any defects.
Semen analysis is also used to check for the presence of sperm following vasectomy.
Do men stop making sperm when they are older?
Unlike women, whose fertility ends at menopause, men can continue to be fertile throughout life. Although sperm production decreases with age, men continue to produce sperm, and even elderly men have fathered children.