I didn’t touch alcohol—literally, not a drop—until a few months before I turned 21. From an early age, I’d known that my grandfather had been an alcoholic, and the common wisdom that the disease skips generations burned in me, leading me to believe that the merest taste would doom me to a short life of addiction bound to end ignominiously in a ditch somewhere. This was an extreme response, perhaps, but I certainly wasn’t alone in how I let stories of my forebears determine my beliefs and behaviors, and in how for years I saw ancestry—with its heady mix of genetics and family lore—as nearly inescapable destiny.

In the same way we talk regularly of certain diseases as hereditary, we also often allow the stories of our grandparents and great-grandparents to influence our behavior and identity. It’s this sticky web of expectations that Maud Newton’s attempts to untangle, sifting through the anxiety of influence that is inheritance, genetics, and how they conspire to create a human life.

Born to an openly racist father who wouldn’t let his children watch the multicultural Sesame Street and who painted nail polish over the brown faces in their picture books, Newton was conceived as a sort of “homegrown eugenics project,” as she explains. “My parents married not for love but because they believed they would have smart children together. This was my father’s idea, and over their brief courtship he persuaded my mom of its merits.” Hoping, perhaps, for Aryan supersoldiers, père Newton got instead two normal children. “Not uncoincidentally,” Newton comments, “nearly every early memory I have of my father involves letting him down in some way.”

Newton’s father held extreme and disturbing beliefs, and Newton broke from them at an early age—another disappointment for him. More widespread throughout our culture, however, is some notion that genetics are destiny, and it is difficult to shake the idea that, on some level, the apple never falls far from the tree. For we are a country that is nothing short of obsessed with blood and lineage, an obsession that Newton troubles at every turn. Her book appears amid popular excitement about genealogy, fueled by websites like Ancestry.com and new DNA technologies, including 23andMe. As she points out, until recently genealogy on any sustained scale was primarily the province of royalty, but recent advances in technology have allowed anyone to construct a family tree as detailed and expansive as the Windsors’. The web has replaced the family Bible as the keeper of the family tree and the stories of one’s ancestors, and now each of us can trace our lineage back centuries.

We look to family trees perhaps because of an interest in history, but ultimately because we want to know more about ourselves. Newton starts with a similar curiosity but quickly moves to more interesting questions. How much of what is inherited is inescapable? What is nature, and what is nurture? The messy process of how we become who we are is shot through by what our parents tell us about our genes and our history, and we inherit not just chromosomes but tall tales about our forebears alongside whispers about black sheep, along with whatever expectations, traumas, and ambivalences our parents imprint on us at an early age. Her point throughout is that ancestry is never destiny, but it’s never not, either.

Ancestor Trouble does what all truly great memoirs do: It takes an intensely personal and at times idiosyncratic story and uses it to frame larger, more complex questions about how identity is formed. Using her own family tree, with its mix of colorful characters, closet-lurking skeletons, and truly vile monsters, Newton recounts the tall tales about these folks she grew up with before revealing what dogged and thorough research has turned up about their actual lives. Sometimes, these ancestors reveal themselves to be of surprising character. A great-grandfather, Charley Bruce, existed in her mother and grandmother’s stories primarily as a man who’d once killed another man with a hay hook. But through scraps of news accounts and trial records, Newton discovers a fuller picture: Charley was attacked by a former friend who’d been convicted of sexual assault of a young girl; Charley had testified against him at trial, and the subsequent attack was revenge, the fatal blow struck by Charley an act of self-defense.

Others are far less redeemable. Newton turns up far more slave-owners in her lineage than she was expecting, not just on her racist father’s side but on her mother’s, as well. And even some potential heroes—such as Mary Bliss Parsons, a distant ancestor in New England once accused of witchcraft—turn out to be far from any kind of role model. Maude Newton, the ancestor after whom Maud (née Rebecca) chose her pen name, was described to her by her mother and grandmother as an idiosyncratic and irascible iconoclast, a woman who chose to live an independent life in Texas. An autodidact who designed and built her own house, and a writer to boot, Maude seemed to have been a kindred spirit, or at least so Newton had hoped. But Maude’s published writings (which took the form of a newspaper column from Drew, Mississippi) reveal a figure enamored with George Wallace and Barry Goldwater, who exhorted her readers to defy the Civil Rights Act to save their “little white girl[s]” from “little Negro boys.” Summing up this disappointing revelation, Newton writes, “I’m sorry that Maude’s writing turned out to be what it was, but I’m not sorry I found it,” remembering, as she does throughout, that we do not dispel the ugliness of the past by ignoring it but by recognizing it and, ultimately, seeking restitution for the sins of the father—and of the great-aunts, as well.

Family stories are one way our forebears pass down legacies to us; Newton also questions the inheritances of genes and heirlooms. The net effect is like watching a deft magician perform one trick after another and then patiently explain the secret and how you’ve been fooled. Newton will offer scientific research to suggest, for example, that mental health or temperament might be something that could be passed down generations, supplemented with detail from her own life (“Later I learned that Charley had died from manic exhaustion,” she says of her great-grandfather, “and I remembered my own sleepless nights and scrabbling brain”). But then she’ll swiftly move to unpack many of the problems with the same theory. She highlights not only the shaky scientific basis for our beliefs (“Our science is only as good as the questions we ask,” she reminds us) but also, quite often, the racist and ableist ideologies that underpin them. The idea of inherited mental traits, for example, which gained currency around the dawn of the twentieth century and still holds sway in popular imagination (and not just with people like Newton’s father), was itself pushed heavily by eugenicists like Henry H. Goddard and his influential 1912 book, The Kalikak Family: A Study in the Heredity of Feeble-Mindedness. But Goddard’s central claim that all of the descendants of Martin Kalikak and his wife were “normal,” while those who descended from an affair with a “feeble-minded” barmaid turned out to be equally “feeble-minded,” was later found to be based entirely on altered and invented data.

What Ancestor Trouble makes clear by the book’s end is that there is something fundamentally misguided about the very question of “nature versus nurture” itself. After all, such a binary implies that human culture, parenting, and environmental factors all exist outside of “nature,” and that our behavior and creations are all fundamentally opposed to the natural world. But when we see “trees and birds and flowers and mountains as ‘nature’ and ourselves and the habitations we build as something apart from nature,” we do not understand that “we are also nature. We are all of the land. Our ancestors back through time have already returned to the earth. We have disavowed that kinship, too.” To truly build one’s family tree requires not just blood relatives but a larger, richer, and more open understanding of lineage and heritage.

By the end of Ancestor Trouble, Newton is far less interested in blood kin than she is in these other possible connections—the ways in which our chosen family and friends, the people who occupied this land long before us, our connection to the land itself make us who we are. As for her blood relatives, she strives to keep the memory of them alive, with all their shortcomings and strengths. Ultimately, Newton turns to more spiritual rituals of grief and mourning—even for those she never knew in life. Because, she decides finally, even though many of her ancestors had grievous shortcomings, “Holding ghosts in a state of unforgiveness makes things worse.” The arc of Ancestor Trouble ends up being a subtle move from a process of genealogical spelunking to one of gentle exorcism.

So the book ends a far sight from where it’s begun, having sloughed off simplistic questions about heredity. Its genius lies in its unmasking of the real motives that drive us to send off our saliva for DNA analysis. In such acts, Newton notes, lies the hope that “we might connect to our ancestors on some mysterious, mystical level, through feelings and tendencies that proteins encode in methyl groups and warning tags placed on our histones.” This, finally, is what it all boils down to: the belief, on some level, that in DNA and chromosomes we might affirm some mystical truth of blood and destiny. Because ultimately, we turn to things like genetics and family history for much of the same reason we turn to astrology. We want answers, and we want to know what’s coming. But as with astrology and other fortune-telling, we see only what we want to see. We want to know the future, when we don’t even know the past.