If scientists are successful the new technique will use RNA interference to block a gene called ZP3 which produces a protein that coats the outside of the egg and "is vital for sperm to latch on to to achieve fertilisation." This would mark "the first serious advance in chemical contraception since the first stages in the development of oral contraception."
Researchers plan to begin full tests on animals within five years and a product could be available within ten.
You can read opposing views of the contraceptive on the f-word blog:
• Just another way to alter our bodies
• In praise of the pill