If you are trying to get pregnant, you may want to know more about one-half of the genetic material that will make a baby. Dallas-Fort Worth Fertility Associates shares six sperm facts about these super swimmers:

  • Sperm cells are produced in the testes over 70 days then temporarily housed in the epididymis.
  • If not ejaculated, the sperm cells are broken down and reabsorbed by the body.
  • Ejaculate is mainly composed of seminal plasma and substances to combat the acidity of the vagina, and is tasked with supporting sperm function. The swimmers occupy only 5% or less of the volume
  • In a man with normal fertility, there are between 20 to  150 million sperm per ml of ejaculate.
  • The average ejaculate volume is about a teaspoon, or 2.75 ml, and ranges from 1.5 to 5 ml. Semen volume is unrelated to fertility.
  • Upon ejaculation, semen coagulates and forms a jelly-like mass. It should liquefy within about 30 minutes. This occurs to protect sperm cells from the acidic vaginal environment. Problems with coagulation and later liquefaction can affect fertility.
  • It takes sperm 5 minutes to 1 hour to arrive in the fallopian tube.


What does a sperm cell look like?

normal sperm

Head – contains the DNA & is covered with enzymes that allow it to ‘talk’ to the egg.

Midpiece – contains mitochondria, which function as a motor to drive the tail.

Tail – a long flagellum that propels the sperm forward.

The sperm determines the sex of the child – all eggs have an X (female) chromosome, and sperm either carry an X or Y, so the resulting child will either be XX- female, or XY – male.

How does the sperm fertilize the egg?

As the sperm approaches the egg, it is activated by chemical reactions that cause the tail to beat more forcefully and rapidly – propelling it strongly forward and allowing it to break through physical barriers around the egg (the outer ‘shell)’. The sperm then goes through 2 chemical reactions, which allowing it to penetrate the egg and release its DNA into the egg. Other sperm are prevented from penetrating the egg by chemical changes that occur very quickly after the first sperm enters.

What’s a normal semen analysis?

• The total number of sperm in the ejaculate should be at greater than 15 million.*
• The total volume should be at least 2 ml.
• At least 75 percent of all of the sperm should be alive.
• At least 25 percent of the sperm should be swimming forward with rapid movement.
• At least 50 percent of the sperm should be swimming forward, even if only slowly.

All of these parameters can vary dramatically between ejaculations.

The reproductive endocrinologists at Dallas-Fort Worth Fertility Associates remind you that a normal semen analysis is not a guarantee of success, but an abnormal result may provide a diagnosis. If you suspect that male infertility is preventing you from starting a family, contact our Dallas fertility clinic to schedule a semen analysis.


World Health Organization Sperm Parameters version V

Male Infertility Semen Sperm analysis

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