A startup's ads for controversial embryo tests hit the New York City subway. One day this fall, I watched an electronic sign outside the Broadway-Lafayette subway station in Manhattan switch seamlessly between an ad for makeup and one promoting the website Pickyourbaby.com, Inside the station, every surface was wrapped with more ads--babies on turnstiles, on staircases, on banners overhead. To his mind, one should be as accessible as the other. Nucleus is a young, attention-seeking genetic software company that says it can analyze genetic tests on IVF embryos to score them for 2,000 traits and disease risks, letting parents pick some and reject others. This is possible because of how our DNA shapes us, sometimes powerfully.

Plus: Meta has taken down a group dedicated to tracking ICE officers' movements An emerging field of science is seeking to use cell analysis to predict what kind of a person an embryo might eventually become. Some parents turn to these tests to avoid passing on devastating genetic disorders that run in their families. A much smaller group, driven by dreams of Ivy League diplomas or attractive, well-behaved offspring, are willing to pay tens of thousands of dollars to optimize for intelligence, appearance, and personality. But customers of the companies emerging to provide it to the public may not be getting what they're paying for. This story is from our forthcoming print issue, which is all about the body. Plus, you'll also receive a free digital report on nuclear power.