Do Female Eggs Attract Sperm?

Yes, female eggs actively attract sperm, but not all sperm equally. Research shows that human eggs release chemicals that attract sperm, exhibiting a phenomenon called cryptic female choice. This means the egg plays a significant role in selecting which sperm fertilizes it.

Studies have demonstrated that eggs don't attract all sperm indiscriminately. Instead, they show a preference for sperm from certain males, and this preference isn't always the female's partner. This selectivity is facilitated by chemical signals, or chemo-attractants, present in the follicular fluid surrounding the egg. These attractants influence sperm behavior and direct their movement towards the egg. The degree of attraction varies; some studies indicate that eggs may attract between 18% and 40% more sperm from a preferred male.

Evidence from Research:

• Differential Attraction: Multiple studies confirm that different women's eggs attract different men's sperm, and not necessarily their partners' sperm. This indicates a complex process of selection beyond simple random chance. [See: Different women's eggs attract different men's sperm—and not necessarily their partners. Lab Manager, June 10th, 2020]
• Chemical Signals: Research pinpoints the role of chemo-attractants in the follicular fluid surrounding the egg. These chemicals are key in the sperm attraction process. [See: Human eggs release chemicals that attract some sperm more than others. New Scientist, June 10th, 2020]
• Cryptic Female Choice: The ability of the egg to selectively attract sperm is considered a form of cryptic female choice, a post-mating sexual selection mechanism. [See: Chemical signals from eggs facilitate cryptic female choice in humans. PubMed, June 10th, 2020]

Implications of Egg Attraction

The egg's ability to attract specific sperm has implications for reproduction. It suggests that the egg plays an active role in fertilization, influencing the genetic makeup of the offspring beyond simple random chance. This process may even increase the chances of fertilization with genetically compatible sperm, boosting the offspring's chances of survival.