“But we have a genetic lifespan kind of predetermined in our genes.” Genes, though, don’t tell the whole story. But as scientists learn more about the building blocks of biological age, tools may help target pathways that shorten lifespan. Genetic screening for conditions like bipolar disorder and kidney disease reveals inherited risks, but no test reliably predicts genetic age. Developing such a tool, Alon adds, would be the first step to improving the genetic lifespan. “Our study will be extra motivation to do those future genetic studies,” he said.