Lauren Sandler is an only child with an only child of her own, who found that discussing the choice to stop at one kid was loaded with anxiety, doubt, misinformation, and judgment. After investigating what only children really are like and whether stopping at one child is an answer to reconciling motherhood and modernity, she learned a lot about herself—and a lot about our culture’s assumptions.

In this heartfelt work, Sandler demystifies the perceived problems of the only child and legitimizes a conversation about the larger societal costs of having more than one. We ask when people are having kids—never a kid, never one child at a time. If parents no longer felt they had to have second children to keep from royally screwing up their first, would the majority of them still do it? And, if the literature tells us—in hundreds of studies—that a child isn’t better off with a sibling, and it’s not something parents truly want for themselves, then whom is this choice serving?

One and Only examines these questions, exploring what the rise of the single-child family means for our economies, our environment, and our freedom. Sandler considers hundreds of studies and interviews, traveling around the world to discover that only children are just fine, their parents often happier, and our planet is better off for them.

Sandler’s controversial revelations will probably draw rebukes from the majority of parents who believe that having several children is the healthiest model for all members of a family. Others will claim that she’s quite possibly cracked the code of happiness, demonstrating that having just one may be the way to resolve our countless issues with adulthood in our overtaxed age.