We all know that conception is a complex process, with many variables at play. But recent studies have shed light on an even more fascinating aspect of fertility—it appears that eggs may actually be able to “choose” which sperm will make it through to fertilization. This means that there are certain qualities that are appealing to eggs and can increase a man’s chance of passing along his genetic material. Let’s look at what this means for fertility.
How Does It Work?
The journey begins when millions of sperm cells enter the reproductive system of a woman after intercourse. From here, only about a hundred or so make it to the very front of her uterus where the egg resides inside its follicle in one of her ovaries. Out of these hundreds, only one lucky sperm will be selected by the egg for fertilisation- but how does this selection occur?
It all starts when hormone levels change due to ovulation, indicating to both eggs and sperm that they are ready for fertilisation. It’s thought that human eggs release chemicals in response to sperm, which essentially allows them to select which sperm will fertilise them. These chemicals are believed to act differently depending on the quality of sperm- the higher quality the sperm, the more likely it is that it will be chosen by the egg. Quality here refers to healthiness and genetic compatibility, infertility issues can arise if either factor is lacking.
The sperms amass around the waiting egg in hopes of being chose, from here, several processes begin to take effect:
- Chemotaxis: this is when certain molecules in a sperm cause certain chemicals within an eggs protective layer to react and draw them closer until eventually make contact with each other.
- Zona Pellucida Reactions: once close enough, particular proteins on a sperm allow it to gain entry into an eggs outer membrane. This triggers changes on both sides that further help ensure compatibility.
- Acrosome Reaction: some substances released by an unfertilised egg activate enzymes on a single sperms acrosome- or head end-allowing it to break through any remaining barriers that can prevent it from entering.
Once inside, genetic material from both male and female components mix together, initiating cell division and eventually resulting in pregnancy! So, as you can see, there us much more involved than initially expected when selecting which sperm will actually make contact with an egg-making mating even more complex than previously imagined.
So, what Does That Mean For Fertility?
In short, if you’re trying for a baby, you want your partner’s sperm to be as healthy and compatible as possible so that it has a better chance of being chosen by your egg. To do this, couples should pay attention to lifestyle factors such as diet and exercise (both have been linked to male fertility) and avoid exposure to toxins like cigarette smoke or heavy metals whenever possible. Additionally, some research suggests that taking antioxidants and repopulating your gut with good bacteria may help improve sperm quality and motility.
The fact that eggs can “choose” which sperm they want is yet another fascinating layer in understanding how conception works—and how we can increase our chances of having a successful pregnancy. So if you and your partner are trying for a baby soon, keep in mind these tips for improving your partner’s fertility and increasing your odds for success!