For years, hopeful parents pursuing in vitro fertilization (IVF) treatment have had the option of screening embryos for severe heritable diseases like cystic fibrosis, hemophilia, and Tay-Sachs disease. These rare and often deadly conditions, known as monogenic disorders, can be easily identified through genetic screening because they arise due to a mutation on a single gene. For doctors, diagnosis is a simple positive or negative. But the diseases that are most likely to shadow the average person's life -- cancer, heart disease, diabetes -- are polygenic, meaning that they result from interactions between thousands of genetic signals. In the past, this has made these diseases -- which kill millions of Americans each year -- all but impossible to screen for with genetic tests. But Genomic Prediction, a New Jersey-based company that analyzes genetic data using machine learning, is hoping to change that.