Wintemute grew up in a home in Long Beach, California, where his father, a decorated veteran of the Second World War, kept a Japanese officer's saber and infantry rifle, a Winchester carbine and a Marlin .22 caliber rifle in a bedroom cupboard. Wintemute learned to shoot, and begged to go hunting. That chance came when he was around 12, and his father asked him to help clear out sparrows from the rafters of his company's warehouse.
Wintemute's aim was good, he recalls. “But I held those birds and looked at the finality of it all and felt them turn cold in my hands and decided this was not for me.”
As an undergraduate at Yale University in New Haven, Connecticut, Wintemute flirted with oceanography and neuroscience, but eventually decided that he wanted to be a physician. After completing medical school and a residency in family practice, both at UC Davis, Wintemute went to work in 1981 as medical coordinator at the Nong Samet Refugee Camp, just inside Cambodia's border with Thailand. The camp was in an area that had only recently been liberated from the Khmer Rouge dictator Pol Pot, and Wintemute took care of gunshot wounds on a daily basis. Even more common were shrapnel injuries from land mines. There was no electricity, and amputations were done under local anaesthetic.
“I never once met an intact family,” Wintemute recalls. “Everybody had lost somebody. There came a point where I said: 'I need to pick up a rifle. I can't be on the sidelines'.”
But instead of grabbing a gun, Wintemute decided to pursue 'big-picture' international health. He left Cambodia and enrolled in a one-year master's program in public health at Johns Hopkins University in Baltimore, Maryland. One of his first courses was taught by a former trial lawyer named Stephen Teret, who is now director of the Center for Law and the Public's Health at Johns Hopkins.
Teret remembers the day in September 1982 when the students of that class introduced themselves and Wintemute stunned him with his charisma and eloquence. “I said to myself: 'I'm going to get to know this guy',” recalls Teret, and the two of them soon became friends and collaborators.
On a cold winter day several months later, some close friends of Teret's dropped their 21-month-old son off at the house of his caregiver. Around noon, the caregiver laid him down for a nap and left the room, whereupon her four-year-old son took his father's loaded handgun from a nearby drawer, pointed it at the sleeping infant and shot him through the head.
Within weeks, Teret switched his main research focus from motor-vehicle injuries to gun injuries, an area in which public-health research was all but non-existent. Wintemute began assisting him, and their first project was a law-review article laying out a legal strategy for suing gun-makers who fail to use available safety technologies to prevent accidental gun deaths.
Wintemute returned to UC Davis, with the goal of focusing on gun injuries. In Cambodia and then in the Sacramento emergency department, Wintemute learned the hard lesson that, as a doctor, he had little chance of saving many people with gunshot wounds; most of those who died did so before they even reached the hospital. He realized that if he wanted to reduce deaths from firearms, he needed to prevent shootings in the first place.
One day, he set himself a question as he left for a run in the foothills east of Sacramento. Looking to make an impact, he wondered: “What subset of firearm injuries can people simply not turn away from?” By the time he got back, he had decided to focus on the kind of shooting that had shattered the lives of Teret's friends.