It’s a fair question. One I expected. When I wrote Chapter One of Drift, I anchored the opening in something that feels unsettling because it is grounded in reality. The rising incidence of certain birth defects, neurological disorders, and developmental conditions is not something I invented for the story. It is reflected in the available data.

In the book, Andrew walks through a series of numbers that feel almost too sharp to ignore. Autism spectrum disorder, for example, was once estimated at fewer than 1 in 10,000 children in 1970. By 1985, that estimate had dropped to roughly 1 in 2,500. Around 2000, it reached 1 in 150. Today, the CDC places it at approximately 1 in 36.

That is a measurable climb within a single lifetime, and it doesn't stop there.

Congenital heart defects were once observed in roughly 1 in 1,200 newborns. More recent estimates place it closer to 1 in 100. Neural tube defects have increased by more than 60% since the mid-1990s, despite widespread folic acid supplementation. ADHD prevalence has moved from around 5% of children to well over 10% in many studies. Speech and language disorders now affect roughly 1 in 12 children.

Each of these numbers can be explained, debated, or contextualized individually. Combined, they begin to suggest something broader. But don’t get lost in the data. The numbers, on their own, don’t tell the whole story.

As I worked through the research, I found that we are better at detecting these conditions than we used to be. Diagnostic criteria have evolved. Screening is more widespread. Imaging technology is more precise. Genetic testing has advanced rapidly, especially in the last twenty years.

In other words, part of what appears to be an increase may actually be visibility. We are finding things now that we simply could not see before.

There’s also the human side of it. Awareness has changed. Conditions that may have gone unreported or misclassified years ago are now documented, tracked, and studied. Families are more likely to seek answers. Physicians are more likely to record them. Public health systems are more structured in how they collect and share that information.

The question becomes (for me): are the numbers rising because something is changing in the world or because we are finally paying attention?

The answer, based on everything I read, is that it’s likely both.

That tension is what has stayed with me since college, when this story first developed. Drift doesn’t try to resolve that question. It really hasn’t been resolved. I think it starts in that uncertainty and takes the discomfort of incomplete explanations forward.

What happens when patterns emerge, but the cause remains just out of reach?

What happens when data begins to suggest something, but the explanation refuses to settle?