Sperm using an appaling sense crashes into walls in race to egg

In recent study British researchers have finally solved the standing puzzle of how human fertilization actually takes place. They revealed that sperms have an appealing sense of direction, smashing into the walls and each other in the race to reach the egg.

Male semen contains three hundred to five hundred millions of sperm, but only one sperm isneeded for conception. Sperm swim through the cervix, into the uterus and by the side of the fallopian tubes.  When sperm travel through the cervix, different chemical changes mature the sperm to make them capable of fertilizing an egg.

Only one sperm becomes able to enter the egg and after that cell membrane hardens and the remaining sperm die. In a joint study by researchers from the University of Warwick and University of Birmingham has found that sperm avoids the middle lane of the female reproductive tract and instead crawl along the channel walls.

The sperms also struggle to turn sharp corners and crash into the walls and each other in a scene reminiscent of a demolition derby. For their study the team injected sperm cells into hair-thin micro channels to study how they behaved in confined spaces. They found sharp turns in the channel caused frequent collisions' as most sperm failed to turn in time.

The successful sperm were those that were best capable to negotiate the intricate and complicated channels filled with sticky fluids. The study was published in the Proceedings of the National Academy of Sciences. It will provide fresh insight how sperm travels through the cervix.


Dr Jackson Kirman-Brown from Birmingham stated earlier research from the group indicates that the shape of the sperm head can subtly affect how the sperm swim. Combined with this data they believe that new methods of selecting sperm may become possible. Through research like this they are learning how the good sperm navigate by sending them through mini-mazes.