Linda Rohr caresses Kate's hand after surgery and writes a card to go with the flowers she had waiting in Kate's hospital room. The couple plan to hold a recommitment ceremony on their 50th wedding anniversary in 2018. (Whitney Shefte/The Washington Post)

To a bright child with a gift for engineering and logic, this mystery of mistaken gender had been something to puzzle over but never question out loud. It certainly couldn’t be shared — not with his parents or his brothers or his friends. Even if they accepted it, what could anyone really do?

So he endured, through a childhood that was confusing and a puberty that was torture. He felt hormones “ravage” his body, turning him unmistakably male. He avoided looking at himself in a mirror, even to comb his hair. But in every other way, he tried to be the best, most typical boy he could be. Growing up in the suburban hamlet of Fanwood, N.J., he played sports and studied hard, and even though he believed God was deaf to his prayers, he dutifully sat next to his parents in church every Sunday.

The days ticked by, and the boy became a man. He married his hometown sweetheart at age 22, graduated from Princeton and went on to earn a master’s degree in mechanical engineering. Medical school put him on the path to becoming an orthopedic surgeon, then a business executive, too. Where other doctors worked 12-hour days, he worked 18. He gave seminars around the world, patented new tools for knee replacements and started a family.

The present became the past, and the young man became middle-aged, but he never stopped thinking about what he’d buried so long ago, never stopped wondering about why and how and what if. At the same time, he knew that if his secret was ever unearthed, it would cost him everything he cherished. There was no map to happiness in this world. How could he know the woman whose love he most feared losing would be the person who would save him?

Life is a “chasing after the wind,” Ecclesiastes says. “Time and chance happen to us all.”

It was a single-column story, low on the front page of the New York Times. College sophomore Bill Rohr picked up the paper and noticed the headline immediately. The first sentence nearly sent him reeling: “The Johns Hopkins Hospital has quietly begun performing sex change surgery.”

The date was Nov. 21, 1966.

The article mentioned Harry Benjamin, an endocrinologist and sexologist who led a foundation spearheading the effort to have transsexuals — a term Benjamin coined — treated as medical, not psychiatric, patients. His book, “The Transsexual Phenomenon,” had just been published. Two days later, Rohr rode a train from Princeton into New York to buy it.

“I was flabbergasted,” Rohr recalled recently. “It described me exactly. It also provided evidence that this was a medical condition and that it was immutable.”

All of it was revelatory, helping him to realize he wasn’t a freak. But that understanding did little to blunt the agony and fear that continued to hold him hostage. Respite from the relentless struggle to be something he was not came only in the library, where late into the night he could turn his mind to books like Benjamin’s.

The physician’s experiences had convinced him that there were untold numbers of people whose psychological, emotional and mental belief of being male or female was opposite to their sexual anatomy at birth. Benjamin thought genetics and prenatal conditions probably played a significant causal role, but because the 1960s and ’70s were the heyday of behaviorism in psychology, nature took a back seat to nurture, as that New York Times article made clear:

“Psychiatrists believe that transsexualism is caused by prolonged conditioning early in life, perhaps within the first three years. Some cases, in which a mother wanted a daughter instead of a son and raised her child accordingly, seem obvious, but the origin of others is obscure.”

Today, an overwhelming number of doctors and scientists dismiss the idea that environment, or behavioral conditioning, causes a person to be transgender. Most agree that sexual anatomy, sexual orientation and gender identity are the result of three distinct developmental processes in the fetal brain. Yet only recently have researchers begun to tease out how that brain is masculinized or feminized. Hormones, it appears, play an essential role.

“As one patient once told me, sexual orientation is who you go to bed with, gender identity is who you go to bed as,” said Norman Spack, a pediatric endocrinologist and co-founder of the Gender Management Service at Boston Children’s Hospital.

Bill Rohr definitely knew the difference. He felt female, believed he was female, but he was also attracted to women — which is why the second time in life he crossed paths with Linda Sue Schwingel, he did everything he could to hold on to her.

They had lived only a mile apart in Fanwood and attended the same public high school. Bill even took Linda to their freshman prom. But six more years went by before they truly got together. Linda had just graduated from junior college, and one day Bill happened to drive by her house. He noticed Linda’s parents sitting on the porch. He drove by the house a second time, then a third. By the fourth time, Linda’s astute mother had alerted her daughter, who was now outside, too.