“There are few genetic guarantees,” she answers, “but that embryo would have a greater than average possibility, with lots of other necessary environmental inputs, of being a very good pure mathematician. Comparing billions of people’s genetics with their test scores over the past 30 years has taught us a lot. Many people with the potential to be great mathematicians never realize that potential, but there are probably no highest-level mathematicians without the necessary underlying genetics.”

Your mind struggles to build a case for nature as it used to seem. “My mother always used to tell me I was perfect just as I was.”

“And you are,” the doctor replies. “We all are. These would all be your natural children just the same as if you had conceived through sex or old-fashioned in vitro fertilization. We’ve simply increased the number of options by turning cells from the blood sample you sent us into the stem cells we used to create more eggs. The great Japanese scientist Shinya Yamanaka won the 2012 Nobel Prize for pointing us in this direction. All of the qualities you’re choosing are entirely your and your sperm donor’s genetic inheritance. We aren’t altering those genetics in any way, just enhancing your choice and limiting your risk.”

You still struggle with the idea that the magic of life can be reduced to a series of percentages on a chart. “Is it really that simple?”

“Nature is no fool. Evolution isn’t random. It just made some trade-offs for us over the years that today don’t always seem that great. We have to approach all of this with a healthy dose of humility.”

Scanning the wall, you don’t see humility. A few low numbers catch your eye. Would it possibly make sense to implant an embryo more likely to get Type 1 diabetes or early-onset familial Alzheimer’s or to die young? You know that people with genetic disorders are just different. Some of them, like some people with autism, even have powers far beyond their so-called normal peers. What would it mean to select these conditions with a simple nod? You fidget nervously. “What if I pick to optimize a characteristic that makes sense today but could be less helpful in a different world tomorrow?”