How much do you know about sperm? Chances are you don’t give these swimmers much thought unless you are interested in having a family or want to avoid pregnancy. However, even if male fertility is not on your mind, there are still some fascinating facts men should know about sperm.
There is a lot of them
The average ejaculate contains about 200 million sperm and takes up about ½ teaspoon. If you placed all of these sperm cells end to end, they would stretch six miles. Another fact about sperm numbers is that they are declining. Recent research named environmental and lifestyle factors behind the more than 50 percent decline in sperm concentration levels over the past four decades.
They undertake a big journey
Sperm cells have a long journey ahead of them once they enter the female reproductive tract. First they must move their way through the cervix, into the uterus, and then travel up the fallopian tubes until they reach a receptive female egg. Very few sperm cells survive this journey, but it takes only one viable sperm cell to fertilize an egg.
They survive for quite a while
Once sperm leaves the body in ejaculate, they can survive for about two to five days inside a woman’s reproductive tract. That’s because sperm can get all the nutrients they need to stay alive in the female body.
They’re in a hurry
Before a man ejaculates, a small amount of semen (pre-cum) leaves the penis. Men have no control over this release and typically don’t even know when it occurs. Pre-cum is released from the Cowper’s gland, which is found at the top of the urethra. Experts don’t agree as to whether pre-cum actually contains any sperm, since its primary purpose is to help lubricate the sperm that is released during ejaculation as well as to reduce acidity in the urethra.
If you and your partner are using the withdrawal method (when the male pulls out of the female before he ejaculates) and also trying to prevent pregnancy, do not depend on this birth control approach. In fact, use of withdrawal to prevent pregnancy is effective only 78 percent of the time. (Note: Withdrawal also does not help prevent sexually transmitted diseases.)
Related: What causes semen to change color
They need to stay cool
Testicles need to be about 7 degrees Fahrenheit cooler than the rest of the body for sperm to stay healthy. The body helps maintain this lower temperature via certain veins that draw heat away and muscles in the scrotum that act like an elevator to raise and lower the testicles to regulate their temperature. Wearing briefs and crossing the legs can increase scrotal temperature by about 2 degrees.
They can even be frozen
Some men have their sperm frozen because they have a medical condition that may have a negative impact on their fertility in the future or if they are undergoing infertility treatment or cancer treatment. Experts believe that sperm cells can survive indefinitely if they are frozen at a stable temperature of around -196 degrees Centigrade. At this temperature, all critical functions of sperm have stopped.
They don’t die easily
It is a myth that sperm dies as soon as it is exposed to oxygen. Sperm cells die when they are dry, and they cannot be revived if they are rehydrated.
They need to be cared for
Men can take many simple, lifestyle steps to help ensure their sperm is healthy and viable. Factors that can result in a lower sperm count or poor sperm function include use of alcohol or recreational drugs, smoking, stress, overweight, overheating the testicles, exposure to industrial chemicals and/or heavy metals, and radiation or x-rays. Use of certain medications, testicular infections or cancer, hormone imbalances, genetic or chromosomal disorders, and surgery that involves the pelvic, reproductive organs, or abdomen all can have a negative impact on sperm health.
Related: Do you have strong sperm?
They like being kept healthy
Men can take many simple lifestyle steps to help ensure their sperm is healthy and viable. These include not smoking, maintaining a healthy weight, reducing or eliminating alcohol use, avoiding recreational drugs (e.g., marijuana, cocaine, anabolic steroids), and eating a clean, all-natural diet. You also want to keep your testicles cool, which means limiting time in hot tubs or saunas, avoiding tight pants or underwear, and not placing your laptop directly on your lap.
CBS News. Sperm: 15 crazy things you should know
Galan N. Facts about sperm health and lifespan. 2017 Oct 12
Planned Parenthood. How effective is withdrawal method?