<p>1 in 11 babies born in America this year will be screened by a genetic test that didn&#39;t exist a decade ago.Biotech startup BillionToOne turned a simple but radical idea—detecting rare fragments of fetal DNA in a mother&#39;s blood—into one of the most widely used prenatal tests in the U.S. And they&#39;re not stopping there. The same approach could unlock something even bigger: early-stage cancer detection from a blood test, a breakthrough that could one day save millions of lives.In this episode of Hard Tech, YC&#39;s Jared Friedman sits down with David Tsao and Oguzhan Atay to hear how they went from half a lab bench to a $4B biotech company—and why they believe this is just the beginning of what their technology can do.</p><p><br></p>