Part of the show Medicine in the Tropics
Researchers from Harvard Medical school announced last week that they may have stumbled upon a way to produce a new kind of contraceptive pill. Scientists David Clapham and Dejian Ren have discovered a tiny channel on the tails of sperms that lets calcium, into the sperm. To swim along, sperms need small amounts of calcium to make their tails move, without calcium the sperms cannot swim and so shouldn't be able to fertilise eggs. To test this theory the researchers genetically altered mice so that they were unable to make this calcium channel in their sperm. These mice were perfectly healthy, and made sperm normally in their testes, but were unable to impregnate females. When sperm from these mice were physically injected into eggs, however, the eggs were fertilised, showing that the sperm were otherwise normal. So how can this discovery help mankind ? Well, the researchers suggest that if a drug can be designed to block the calcium channel, which is only found in sperms, a man's sperm would be immobilised and so not be able to swim to the egg and fertilise it. Better still, this pill could be taken by a man or a woman. Very unisex !