London: A scientific breakthrough claims to have opened the way to a non hormonal contraceptive pill for women, which will be free of side-effects.
Lab experiments show a hormone released by an egg ready to be fertilised acts as a `come hither` message to sperms which then react in a blink.
The discovery means it may be possible to develop a non-hormonal pill to turn the signal off, the journal Nature reports.
Researcher Polina Lishko and colleagues at the University of California, US, carried out experiments on mouse and human sperm to investigate how they detect an egg ready for fertilisation, according to the Daily Mail.
They measured the electrical currents that drive the wiggling movements of a sperm`s tail on its journey towards an egg newly released from the ovary.
They found that when the sperm gets a boost of progesterone, a hormone released by cells surround the egg, the electric current get a boost and their tails move faster.
Developed in the 1960s, the pill is credited with giving women sexual freedom. But it can cause dangerous side effects, such as increased risk of blood clots, high blood pressure and breast cancer.
It works in women by using hormones to suppress ovulation - the release of an egg. As there is no egg to be fertilised, pregnancy cannot occur.
But now scientists believe they have discovered a chemical, CatSper, a calcium channel on the sperm that is attracted to the hormone progesterone which is released by eggs.
Scientists say it would be possible to create a non-hormonal drug that prevents the process and, as a result, stops sperm from swimming towards the egg.