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.
But even though researchers know female mice react differently to drugs to males, there have been zero studies on separate interventions that could help women live healthier, longer lives.
A sobering example is from 1993, when the first papers on low methionine diets were published. The results were stunning: the diet was found to extend life by more than 40% in rats. Several follow-up studies were done throughout the 1990s, all showing the same astonishing results.
It took 12 years before it was pointed out that the rats in every single study had been exclusively male, and that perhaps it would be a good idea to test on females too. When the study was redone with females, it found the life-giving diet for males caused a number of the females to die early.
Source: Why sex bias in labs means women are the losers in research into ageing