Human eggs appear to "choose" which sperm will become the lucky winner in conceiving a baby. The study discovered that that eggs attract between 18% and 40% more sperm from the preferred male. Sperm, as it turns out, have odor receptors in their heads that respond to the chemoattractants in the egg's follicular fluid, thus influencing how vigorously the sperm swims. "So when sperm go into the follicular fluid, they start to go straighter and they start to change the way they swim," Fitzgerald said. Couples who are currently experiencing infertility, however, shouldn't worry about whether or not they have sperm and follicular fluid compatibility problems, he added.

Source: CNN June 09, 2020 23:15 UTC