This story begins in a Tot Lot playground on Manhattan’s Upper West Side. Watching her three-year-old son play, author Annie Murphy Paul wonders: “What makes you the way you are?” Every human life is unique and irreplaceable, full of wonder, beauty, and mystery; no one quite knows how we get to be who we are, but that doesn’t stop us from speculating. At the Tot Lot, Paul is told that her son has his father’s professorial temperament and his mother’s journalistic sensitivity, “as if his personality traits were lottery numbers drawn at conception.” Then there are the crucial first years after birth, in which nature and nurture play their eternally disputed parts.
To these important factors we must now add another: fetal origins. This is a burgeoning new line of research, which Paul, a science journalist, ably investigates and presents to general readers. She describes how our prenatal environment influences the expression of our genes, how this unwitting nurture in the womb shapes our nature — not only the growth of our physical organs, but our health, appetites, intelligence, personality, and even lifespan. While the book is not as well organized as one might have hoped — and a bit thin toward the end — it’s engagingly written and full of interesting facts and figures.