Whenitcomes to sp’erm, people always seem to have an agenda.
Some want to kill sp’erm cells. Some want to buy or sell them. Some fret over their failure to get the job done.
Why can’t we just appreciate sperm for the amazing little wrigglers that they are? After all, without sperm, the world would be a very lonely place.
So here are 15 fascinating facts about sp’erm, from Dr. Craig Niederberger, professor of urology at the University of Illinois at Chicago.
Abnormal Spe’rm? That’s Normal
Human spe’rm-making machinery is a bit lazy. How else to explain the fact that 90 percent of the sp’erm in a man’s ejaculate are deformed? Two heads, two tails, huge heads, pinheads, coiled tails – the list of common deformities is a long one.
It’s the price of monogamy, Dr. Niederberger says. “For those species where more than one male’s sperm can find itself in a female at the same time, the spe’rm are much more uniform in appearance,” he says. “In humans, Joe and Sam’s sp’erm don’t usually find themselves in Betty at the same time.”
Half a Teaspoon
That’s how much a man typically ejaculates. It isn’t much, but – for better or worse – it often does the job.
Sp’erm Wear Hard Hats
You might not call s’perm dapper, but they do wear hats.
Well, not really a hat but an oval-shaped structure called the acrosome. It contains strong chemicals that are released once the s’perm attaches to the egg. The chemicals melt the egg’s outer surface, drilling a hole so that the sperm can penetrate the egg to release its genetic cargo.
Sp’erm vs. Semen
Some people use the terms sperm and semen interchangeably. But s’perm cells are only one component. Semen also contains substances from the prostate and a pair of rabbit ear-shaped organs inside the pelvis called the seminal vesicles.
Spe’rm cells – which are made in the testicles – need lots of high-octane fuel to whip their tails. Lucky for them (and us), s’perm get the fuel they need in the form of sugar fructose, which is supplied by the seminal vesicles.
Fluid from the prostate contains chemicals that cause semen to liquefy once it’s inside the female. Without it, sp’erm would be locked in place and unable to swim.
One Testicle Is Enough
If a guy loses one testicle, the other is generally able to make enough sp’erm to create a baby. Often the remaining testicle grows a bit to boost spe’rm output.
Lance Armstrong, shown here, is perhaps the most high profile person to have lost a testicle to cancer. He has fathered five children since then, three from banked sp’erm, but two, he says, were concieved naturally.
200 Million Competitors
It takes only one sp’erm cell to fertilize a woman’s egg – but there’s stiff competition for that honor. In fact, the average ejaculate contains 200 million sp’erm. Best of luck to each of you.
The Factory Never Closes
Women are born with all the eggs they’ll ever have. It’s different for men. Men produce sp’erm all day, every day – throughout their lives.
As men age, their s’perm may become a little sluggish and their DNA a bit more fragmented. But the factory never closes.
Hope springs eternal.
Sperm Are Tiny
Want to see a sp’erm cell? Better have a microscope, because sp’erm are far too tiny to see with the naked eye. How tiny? Each one measures about 0.002 inch from head to tail, or about 50 micrometers.
Of course, what sp’erm lack in size they more than make up in sheer numbers. If a guy could coax all the sp’erm in one ejaculate to line up end to end, they’d stretch six miles.
That’s a lot of sperm.
Sp’erm Need Protection
Sp’erm start out looking pretty much like any cell in the body. But by the time they’re ready to leave the testicles, they have half as much DNA as other cells in the body. That makes them look a bit suspicious to the body’s immune system.
To keep immune cells from wiping out “invading” spe’rm, the testicles employ specialized cells to surround them with a sort of “picket fence.”
Dead Sp’erm Can Make Live Babies
To fertilize an egg the old-fashioned way, spe’rm need to be able to swim. Not so with in-vitro (test tube) fertilization. In fact, when IVF technicians use tiny, robotically controlled glass straws to insert a single s’perm inside an egg, they sometimes beat the sp’erm with the glass until it stops moving. The only thing that matters is the DNA inside the sp’erm.
Which Way Do We Go?
Sp’erm can certainly whip their tails, but many have a hard time swimming in a straight line. In fact, only about half do. The rest swim around in circles or bob along with the motion of the semen.
But because so many start their journey, plenty make it to the egg. And that’s despite the fact that the tubes connecting the uterus to the ovaries contain tiny hair cells that beat against the sperm.
Ever seen salmon swim upstream? It’s a bit like that.
Sperm Live for Days
How long can a spe’rm cell live once inside a woman’s body? About two days.
The Y Stands Alone
Once a spe’rm fuses with an egg, the chromosomes swap bits of DNA, meaning that each becomes a mash-up of mom’s and dad’s DNA. But there’s one exception: the Y chromosome has no counterpart within the egg’s DNA, so it’s passed along essentially unchanged from father to son.
In fact, a man’s Y chromosome looks just like his father’s and his father’s father’s, and so on, back through the generations.
Se’xual passion may be hot, but a guy’s testicles stay cool – about 7 degrees Fahrenheit cooler than ordinary body temperature. That’s just right for producing healthy sperm.
A man’s body keeps the ideal testicle temperature with radiator-like veins that pull heat away and muscles in the scrotum that raise and lower the testicles to bring them closer to the body’s warmth – or farther away.
If a guy crosses his legs, his scrotal temperature increases by about 2 degrees. Ditto if he wears briefs. But lots of guys who cross their legs become dads, and Dr. Niederberger says the idea that wearing boxers will help boost fertility is probably misguided.
Two Months to Make Sp’erm
How long does it take to make sperm? About two months, according to the latest studies.
“Spe’rm are being started all the time, just like an assembly line,” says Dr. Niederberger. “You don’t wait for a truck to finish the assembly line before starting to build another, right? But just like an assembly line, it takes time to go from the start to the end.”