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Sparks Really Do Fly in an Unexpected Place During Sex

Scientists have proven that sparks of zinc fly out of a human egg when a sperm penetrates its outer membrane at the moment of conception. How does one get a job as a volunteer for these experiments and where does the line start?

It has been known for a few years that zinc sparks fly out of eggs when the winning sperm hits them due to experiments involving mice, pigs and non-human primates. Researchers found that calcium levels in the egg rise during conception and this triggers a fluctuation in zinc levels which, in an enclosed space like an egg, causes the zinc to burst out of the membrane in a visible spark.

Outside of a sign of excitement and celebration, does the spark have any other significance? It turns out the quality and size (yes, size matters in sparks) of the zinc spark is an indication of the health and future potential of the fertilized egg. In other words, the bigger the spark, the bigger and healthier the mouse, pig or chimp.

Is this the case in humans too?

All of biology starts at the time of fertilization, yet we know next to nothing about the events that occur in the human.


Teresa Woodruff, a professor of obstetrics and gynecology, and a team of researchers at Northwestern University decided to find out. According to their study results, published in Scientific Reports, they suspected that seeing the zinc spark and measuring its intensity could help determine which eggs were the best candidates for in vitro fertilization. The results proved them correct.

This means if you can look at the zinc spark in the time of fertilization, you will know immediately which eggs are the good ones to transfer in in vitro fertilization (IVF). It’s a way of sorting egg quality in a way we’ve never been able to assess before.

Woodruff says the spark gives fertility doctors a way to tell if an egg is healthy without using current invasive procedures that can damage the egg in the process.

Right, right. So, where does the line form for volunteers with unusually large … um … sparklers? They could tell you but then they’d have to kill you. The eggs used in the experiment were not fertilized with real human sperm because that kind of experimentation is against federal law in the U.S.

If you want to make real sparks fly in the bedroom, wear rubber-soled slippers and shuffle your feet on a wool carpet before jumping into bed. You also might want to warn her first.



Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.
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