Extending the human lifespan is a multibillion-pound industry and has been hailed as the most fascinating scientific challenge in modern history. But if a drug to achieve longevity is ever discovered, one thing looks certain: it is highly unlikely to work on women – and almost inconceivable that it will work on mothers.

That is because, say experts, cages in laboratories across the world are filled with white mice who share a striking similarity: they are all male.

This is a serious problem, said Dr Steven Austad, a biologist and the author of the bestselling Methuselah’s Zoo, because the sex differences between rodents are significant – and the differences between virgin female mice and mice that have given birth are even larger.

About 75% of the drugs that extend lifespan in mice work only on males: the drugs were developed on male mice then belatedly tested on both sexes, only to discover the females did not respond.