We say it all the time – the human body is an incredible piece of machinery, and a fascinating study really underscores its sophistication. Chemical-based preferences that steer women toward specific men appear to play out between the human egg and sperm, with the egg “choosing” which sperm will be the lucky winner in the race to fertilization. Spoiler – the higher quality the sperm, the better the odds of a successful journey and conception. Here’s what that means for fertility.
- Human eggs release special chemicals that behave differently on different sperm, essentially “choosing” the sperm they deem the most acceptable.
- The most acceptable sperm is thought to be the healthiest, with the most genetically compatible DNA.
- The journey to the egg is dangerous for sperm – of the tens of millions that start, it’s estimated that just 250 will make it to the egg. That’s why a good supply of the strongest, most robust sperm is so important for a successful conception.
- Healthy sperm starts with a healthy lifestyle, including supplementing with a high-quality men’s prenatal vitamin.
The Egg Calls the Shots
It’s been established that human eggs release special chemicals known as chemoattractants, which sperm use to find their way to unfertilized eggs. But a 2020 test tube study published in journal Proceedings of the Royal Society found something else. Researchers used follicular fluid and sperm samples left over from 16 couples undergoing reproductive treatment. They conducted various experiments that exposed sperm to follicular fluid, complete with a long swim across a petri dish to mimic what happens in a woman’s body. Pull on your science caps, and let’s get technical.
The chemoattractants released by human eggs can behave differently on different sperm – likely those carrying the most genetically compatible DNA. In mammals, genetic compatibility boils down to greater diversity, which is directly related to an improved chance of offspring survival. In fact, just about everything related to human reproduction is geared toward rewarding the most compatible mate. Sperm have to navigate a treacherous uphill obstacle course and fight off defenders from the female’s immune system, which see them as invading attackers. If they survive passage through the cervix, sperm then face a life-or-death choice about which fallopian tube to take in their search for the egg.
Researchers estimate that of the tens of millions of sperm that start this arduous journey, just 250 will make it to the egg. Of those, roughly 10% are capable of fertilization. And it’s here, in the last few centimeters the sperm has to travel, that the egg sends out its chemical signals to the most acceptable of these final contenders. Odor receptors in the heads of sperm respond to these signals, motivating them to swim harder, faster, and more directly – a final sprint to the finish line, as it were. What’s more, the egg can send chemical signals to the sperm it doesn’t want, effectively slowing down their swim pattern.
The Best Sperm Wins
While this is all terribly interesting and exciting, researchers are quick to point out that more studies are needed to see if this discovery can be used in couples dealing with unexplained infertility. Still, it highlights the importance of the most robust sperm, and science has already told us what can be done to promote that:
- Prioritize a healthy lifestyle. Health as a whole is a good representation of fertility health, which is why experts advise couples hoping to conceive embrace healthy habits. That includes regular exercise, solid nutrition, stress management, and minimizing exposure to environmental toxins. Our recent post about resolutions for hopeful parents-to-be in 2023 is a great place to start!
- Supplement with specific nutrients. One of the biggest culprits of sperm deficiencies is a nutrient shortage during the three-month sperm maturation process. Swapping a men’s multivitamin for a high-quality men’s prenatal vitamin is a small act with a big pay-off – a steady supply of vitamins, minerals, and antioxidants shown to support and promote sperm health across all quality parameters.
The Bottom Line
Keep in mind, sperm quality and concentration are on the decline world-wide, and it’s estimated that just one man in four has optimal sperm health. While science focuses on turning discoveries like this chemical bread trail into actionable treatments, we do what we can. And for now, that means sticking to the basics – embracing healthy lifestyle habits and a good men’s prenatal vitamin. After fall, pregnancy is a numbers game, and the more robust sperm you start with, the greater the odds that the right sperm will make it to the finish line.