A contraceptive pill that could be taken by men as well as women has come a step closer to being developed.
A breakthrough in the understanding of the biology of sperm could lead to a unisex version of the Pill, US government-funded scientists said last night.
They have identified a protein in sperm that gives it the energy it needs to power towards the female egg and break its way into it.
As the researchers put it, the ABHD2 protein allows the sperm's tail to "crack like a whip" and "power kick" its way into the egg.
Dr Stuart Moss, of the US National Institutes of Health, said: "Developing new compounds that block ABHD2 ultimately may yield new contraceptive methods that prevent sperm from reaching the egg."