T. Berry Brazelton, a pediatrician whose best-selling guides to child-rearing soothed generations of parents, assuring them that they need not seek perfection and that the answers to many of their questions lay before them in their children’s behavior, died March 13 at his home in Barnstable, Massachusetts. He was 99.

His daughter-in-law, Jennifer Brazelton, confirmed the death but did not provide a specific cause.

Dr. Brazelton was perhaps the best-known American pediatrician since Benjamin Spock, who revolutionized child-rearing by counseling parents to rely on their “own common sense” rather than on commandments dispensed by purported experts.

Brazelton – who described Spock as his “hero” and who counted Spock’s grandchildren among his patients – picked up where the older physician left off. In books such as “Infants and Mothers” (1969), in his hit “Touchpoints” book series, in commentaries published in Redbook and Family Circle, and on the Emmy Award-winning television show “What Every Baby Knows,” Brazelton genially coached parents to see their children’s abilities as well as their own.

He bucked prevailing notions of his time by arguing that babies are not “lumps of clay” but rather expressive beings whose behavior conveys their needs. Rather than instructing parents on child-rearing, he sought to help them read their babies’ cues.

“People assumed babies were all the same and that it was parenting and the environment that made the difference,” Brazelton told USA Today in 2013. “We were blaming parents for everything that went wrong with babies. I thought if I could assess these babies early . . . we could use this in understanding the child more and give the parents a better chance of understanding the child, too.”

Brazelton spent much of his career in Massachusetts, where he held appointments at Harvard Medical School and Boston Children’s Hospital and where he maintained a private pediatrics practice in Cambridge.

In 1973, he developed the Neonatal Behavioral Assessment Scale, often called the Brazelton. The now-widely used test relies on simple tools such as popcorn kernels and a pocket flashlight to test a newborn’s response to sound and light. He identified three broad categories of babies: average, quiet and active.

Besides helping new parents decode an infant’s needs, the test changed adoption practices by allowing physicians to quickly gauge a baby’s health. Traditionally, babies awaiting adoption were institutionalized for months of observation before placement.

Brazelton contended that neither children nor their adoptive parents could afford to lose those critical early months of bonding.

Although the scale was widely regarded as one of Brazelton’s most significant contributions to medicine, his reach extended far beyond hospitals, into homes and the most intimate decisions parents make. On his television show, he was said to project a “combination of Sigmund Freud, Mister Rogers and Phil Donahue.” Mainly, he tried to persuade parents not to worry so much.

“Parents care so much they can’t smile,” he told an audience in 1979. “They can’t smile and give children a feeling of the excitement of being a parent. I would like to look at what can be done to get parents to relax and not to take [parenthood] quite so seriously.”

He assured those with picky eaters that “children always eat better for people other than their mothers.” Neither should bickering cause parents too much consternation. “Fighting,” he observed, “is how siblings learn about each other.”

He especially sought to comfort strung-out mothers.

“Parents are surprised and even ashamed at their own lack of endurance with small children,” he wrote. “But they needn’t be. There is nothing so exhausting as giving attention constantly to someone else.”

Brazelton was known particularly for a series of books, beginning in 1992, on developmental milestones that he dubbed “touchpoints” – moments when children are on the cusp of a great leap, such as learning to walk, and tend to regress by crying, refusing food or otherwise acting out.

By anticipating and understanding touchpoints, he hoped, parents might be better prepared to confront them – and to celebrate the accomplishments that follow.

“Most issues in parenting involve a spurt in the child’s autonomy and the parent’s need to control,” he told the New York Times. “It helps to see things from the child’s side.”

On the contentious (and often messy) matter of potty training, he advocated what he described as a “child-oriented approach,” saying that parents should allow their youngsters to shed the diaper when they showed signs of readiness, rather than working from a preestablished timetable.

It was a controversial position, opposed by more-conservative parenting experts who lamented permissiveness in parenting. John Rosemond, a child psychologist, advocated what he described as the “naked and $75” method. (The label has resisted inflation.) Parents who employ it keep their child unclothed and within easy reach of a portable potty during training – and set aside $75 to shampoo the carpet.

Brazelton told the Times that the idea that a child should be housebroken like a puppy was “very logical – for a puppy.”

Some of his views evolved over the years with changing social attitudes. After long arguing that mothers should stay home with young children, he acknowledged in the 1980s that some women needed to work outside the home and found fulfillment in their professions. He credited his transition to his daughters, who he said had told him, “Dad, you are out of this century.”

He became a chief proponent of mandated maternity leave and encouraged working parents to “cheat on the workplace” so they would have the emotional reserves to fully care for their children when they were not on the job. The greatest gift a parent could give, he said, was a loving home from earliest infancy.

“Babies are competent to withstand ‘mistakes’ that their inexperienced parents might make,” he wrote in “Infants and Mothers,” “and even to let the parents know when they are on the wrong track.”

Thomas Berry Brazelton Jr. was born in Waco, Texas, on May 10, 1918. He recalled being distant from his father, who ran the family lumber business but was away for military training when he was born. Brazelton’s mother served on the local school board and reportedly helped found one of the first abortion clinics in Texas.