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The Vermont lake was the perfect setting for a mother-daughter day. The mother packed water and towels. The daughter, an excitable young girl, shoved cheese sticks into a cooler. When the two arrived at the beach, they swung the cooler between them as they walked to the water.

But the mother’s smile was strained, because the day of family fun would be closely watched. Joining the pair was Sharon Lamb, a psychologist who evaluates parents and makes recommendations to family courts regarding whether their rights to their children should be terminated. The daughter had been in foster care for two years, and her mother was in danger of losing custody permanently. Lamb was there to help determine whether the mother could be considered fit to parent.

Throughout the day, Lamb took notes on whether the daughter felt close to the mother. She observed smaller details too—such as whether the mother remembered to pack food and sunscreen for her child. Shortly after they arrived, the mother ran into the water, leaving her daughter behind on the sand, where the daughter timidly watched in a baggy bathing suit. “Was I wrong to expect what I would have preferred to see? More encouragement for the hesitant little girl …?” Lamb writes in The Not Good Enough Mother, a new book that details the lake trip and other anonymized anecdotes from Lamb’s work.

After dropping to a historic low in 2012, the number of children in foster care has steadily increased in recent years. The number entering foster care because of parental drug use, in particular, has more than doubled since 2000 as the opioid crisis has consumed the United States. Lamb and psychologists like her are the ones tasked with helping to decide what will happen to these children. They find themselves in a difficult situation: Based on just a few, stilted interactions, they must describe the true nature of the bond between a child and a mother—she’s usually a single mother, Lamb says—and predict how it will play out into the future. If the mother’s care seems unsafe, they must recommend separating her from her child, an outcome most Americans find tragic.

Lamb recognizes the importance of preventing abuse and neglect, but she nevertheless feels some unease about helping to make distinctions between good and bad mothers. Does running into the water without your child make you a bad mom? Does packing cheese sticks make you good enough? If not, what does?

Lamb is a psychology professor at the University of Massachusetts in Boston. Separately, she also takes two or three of these child-custody cases each year. “They’re so stressful,” she told me in an interview. At one point in her book, Lamb mentions she has considered giving up these types of evaluations altogether. She began doing them shortly after she moved to Vermont in 1996, when a local attorney called her to evaluate the case of a boy in foster care. That led to her name being bounced around listservs of family-court lawyers.

Typically, Lamb says, the Department of Children and Families calls her in to evaluate cases involving younger kids who have been in foster care for more than a year and whose parents still aren’t improving. In more than half the cases she works on, the judge permanently places the child with a new family. Lamb told me she sometimes does evaluations for parents’ attorneys, too, who want her to show the courts that their clients are fit.

To be clear, parents who are in danger of losing their children have done more than simply hurt their kids’ feelings at the beach. Typically, Lamb and other experts told me, those parents’ cases involve multiple reports of abuse or neglect, including heavy drug use at home and a failure to take advantage of the help offered by social workers. A neighbor might call because a 2-year-old is left unattended; a teacher might call because a child is not coming to school. Some parents are isolated and friendless, and child protective services is the final net that catches them. It is the point at which the state says that adults might live that way, but children can’t.

Lamb understands all this, but in a deeply personal way, she also knows how even the best-intentioned parenting can’t prevent every calamity. Lamb’s own son, she writes, struggled with addiction. At one point in the book, she weighs what she calls “motherlove”—the special connection between a birth mother and her child—against “the stability of a foster home.” She asks herself, What kind of stability did I provide? and wonders whether her mothering contributed to her son’s addiction. One section is dedicated to the slog of finding a rehab facility for her son, and several more to the lies and worries that come with having an addicted family member.

For her evaluations, Lamb follows clinical guidelines, which include observing the adults in their role as parents, as she was doing with the mother and daughter at the lake. She describes a mother who mocked her child for hurting herself, instead of kissing her finger—a sign, Lamb told me, of “not being able to cope with a child who needs something from you.”

She also carefully studies how children react to their birth parents. One thing she looks for is what’s called “secure attachment,” or an impression that the child can depend on the parent to be there when the child feels unsure or afraid. “Insecure attachment,” meanwhile, could manifest itself in several ways. Anxious attachment might mean an extremely clingy child; avoidantly attached children act as if they don’t need the parent; a disoriented child freezes or simply doesn’t know what to do.

Even when everyone—the evaluator, the social worker, the judge—tries to execute her part perfectly, the child-welfare system can be heart-wrenching and unfair. Much of what determines whether parents’ rights are terminated is how well they work with their social worker, says Julianne Woolard, an attorney who has worked with Lamb. The process can require a level of social skills and diplomacy that many people—especially low-income mothers and fathers—haven’t learned. “It’s sitting through meetings with 10 people at a table, talking about you, talking about your parenting skills,” Woolard says. “It’s tough.”

Certain parental afflictions tend to be punished more harshly than others. Fetal alcohol syndrome is shockingly widespread, but as Lamb writes, “If we removed children from all the homes of people struggling with alcoholism, it would be hard to find enough foster homes for these kids.” And Lamb repeatedly describes how we—society, the system, and sometimes even children themselves—seem to expect much more from mothers than from fathers. “Mothers who don’t protect are always worse than fathers who abuse,” she writes.

Parents themselves vary widely. Poor people and rich people often have different definitions of “good enough” parenting; they might have been raised differently and cope with different amounts of stress in adulthood. A parenting tactic that is merely strict in one mother’s hands can appear cruel when performed by a mother who is already considered suspect.

Money, in part, determines who gets to be mean with impunity. The infamous “tiger mother,” Amy Chua, has said she once rejected her children’s handmade cards because they weren’t made with enough care. At one point in the book, Lamb hints that had a less wealthy and accomplished mother treated her children that way, she might have lost access to her children. It would be rare, Lamb told me, for somebody to report a wealthy-looking mother to the police if she were seen criticizing her child in public. “It’s interesting to think about who has a right to be verbally abusive to their child, and it seems like with money, you do have that right,” she says.

Just as money can protect parents, the lack of it is often what creates the conditions for abuse and neglect. One prosecutor in Texas, who wished to be anonymous in order to speak freely about his small town, told me several years ago that he sees many children left at home with ill-equipped “baby daddies” because the mom has to work and can’t afford child care. Or families cram into old trailers and have milk spoiling in a broken fridge. Even getting to a church that’s giving out free diapers requires a car.

Ultimately, family courts have to determine whether parents will provide adequate care for their children. It’s not a question of whether the birth parents outperform the foster parents. It’s a matter of whether they are, essentially, good enough. “You’re looking for stability for the child … It doesn’t have to be excellent care,” says Pam Marsh, a Vermont lawyer who mostly represents children in child-welfare cases. “You don’t have to get the Mother of the Year Award or the Father of the Year Award to get your child back.”

Toward the end of her book, Lamb settles on a definition of “good enough” parenting: being able to understand what’s in the mind of your child. In our interview, she described it as a kind of empathy, of recognizing your child as a whole person and caring what he or she thinks and feels. It’s seeing a child who is having a meltdown and thinking, She’s really mad because I had promised her that I would have this treat and I forgot it, Lamb says, rather than thinking, She’s just spoiled.

The book is not a call to reform the child-welfare system. In our interview, Lamb imagined one kind of intervention, though she acknowledged it’s hardly practical or likely to happen: The best approach, she speculated, might actually be a foster home for the least functional parents she sees. That way, those parents could themselves be “parented in a foster home while their kid was being parented in a foster home,” she says. It might be the only way to help these traumatized and struggling parents get to “good enough”—and beyond. A mother who messed up, used drugs, failed to come to appointments, or kiss the hurt finger, Lamb says, “needs that kind of love.”

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