Human eggs have a love affair with certain sperm

only a small fraction of the sperm can eventually reach the egg. Photo Source: Alexey Kotelnikov/Alamy
A new study published in the Proceedings of the Royal Society B suggests that human eggs may release chemicals to attract sperm with certain traits, which may affect their likelihood of conceive with a particular partner.
first time this phenomenon has been found in humans or other fertilized species," said John Fitzpatrick of Stockholm University in Sweden. The
Fitzpatrick and colleagues studied samples of sperm and follicle fluid taken from 16 couples receiving infertility treatment. Follicle fluid is a nutrient-rich liquid that surrounds the egg cells during development and release, and sperm swims through the follicle fluid to reach the un fertilized egg.
researchers found that each woman's follicle fluid attracted more sperm from certain men. There is no obvious pattern to explain which man's sperm is attracted to a woman's follicle fluid.
seems random and has no inevitable connection to the partner chosen by the woman. "It was a real surprise." Fitzpatrick said.
researchers measured the amount of sperm that could enter each follicle sample. They found an average difference of about 18 per cent in sperm count between follicles that attracted the most sperm and lowest sperm.
Fitzpatrick said, "The egg can attract an 18 percent more sperm from a particular male, which may be important for the fertilization process in the female reproductive tract" because only a small percentage of sperm ends up reaching the egg.
it is possible that eggs are more susceptible to gene-compatible sperm, which may increase the chances of fertilization of eggs, Fitzpatrick said. The chemical effects between eggs and sperm after sex may also be one of the reasons why some people find it difficult to conceive. About one-third of couples have an unknown reproductive problem, Fitzpatrick said.
Eisenbach of the Weizmann Institute of Science in Israel, said the study may show that egg attraction to sperm plays a previously unknown role in mammals. Future studies should test whether these results also appear in chemicals produced by mature eggs released after ovulation, he said, because the follicle fluid contains chemicals produced before the eggs are fully ripe.
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