I WAS one of the first women in the San Francisco Fire Department. For more than a dozen years, I worked on a busy rig in a tough neighborhood where rundown houses caught fire easily and gangs fought with machetes and .22s. I’ve pulled a bloated body from the bay, performed CPR on a baby and crawled down countless smoky hallways.

I expected people to question whether I had the physical ability to do the job (even though I was a 5-foot-10, 150-pound ex-college athlete). What I didn’t expect was the question I heard more than any other: “Aren’t you scared?”

It was strange — and insulting — to have my courage doubted. I never heard my male colleagues asked this. Apparently, fear is expected of women.

This fear conditioning begins early. Many studies have shown that physical activity — sports, hiking, playing outdoors — is tied to girls’ self-esteem. And yet girls are often warned away from doing anything that involves a hint of risk.

One study focused on, coincidentally, a playground fire pole, is particularly revealing. It was published in The Journal of Applied Developmental Psychology and showed that parents cautioned their daughters about the dangers of the fire pole significantly more than they did their sons and were much more likely to assist them. But both moms and dads directed their sons to face their fears, with instruction on how to complete the task on their own.

I spoke recently to a friend who admitted that she cautioned her daughter much more than her son. “But she’s very klutzy,” the mom explained. I wondered, wasn’t there a way even a klutzy child could take risks? My friend agreed there might be, but only halfheartedly, and I could see on her face that maternal instinct was sparring with feminism, and feminism was losing.

I had been a klutzy child, too. I was also shy, and scared of many things: big kids, whatever might be under my bed at night, school. But I pored over National Geographic and “Harriet the Spy.” I knew all about Sir Lancelot and the Knights of the Round Table, who wandered the countryside swearing oaths of bravery and honor. None of these characters talked about fear. They talked about courage, exploration and exciting deeds.

So I biked down a steep country road (and hit a car). I sledded down an icy hill (and hit a tree). I don’t remember my parents freaking out; they seemed to understand that mishaps were part of childhood. I got a few stitches, and kept biking and sledding. Misadventures meant that I should try again. With each triumph over fear and physical adversity, I gained confidence.

I recently asked my mother why she never tried to stop me. She said that her own mother had been very fearful, gasping at anything remotely rough-and-tumble. “I had been so discouraged from having adventures, and I wanted you to have a more exciting childhood,” she told me.

My mom is an outlier. According to a study in The Journal of Pediatric Psychology last year, parents are “four times more likely to tell girls than boys to be more careful” after mishaps that are not life-threatening but do entail a trip to the emergency room. It seems like a reasonable warning. But there is a drawback, and the researchers remarked on it: “Girls may be less likely than boys to try challenging physical activities, which are important for developing new skills.” This study points to an uncomfortable truth: We think our daughters are more fragile, both physically and emotionally, than our sons.

Nobody is saying that injuries are good, or that girls should be reckless. But risk taking is important. Gever Tulley, the author of “50 Dangerous Things (You Should Let Your Children Do),” encourages girls and boys to own pocketknives, light fires and throw spears, arguing that dangerous activities under supervision can teach kids responsibility, problem-solving and confidence. It follows that by cautioning girls away from these experiences, we are not protecting them. We are failing to prepare them for life.

When a girl learns that the chance of skinning her knee is an acceptable reason not to attempt the fire pole, she learns to avoid activities outside her comfort zone. Soon many situations are considered too scary, when in fact they are simply exhilarating and unknown. Fear becomes a go-to feminine trait, something girls are expected to feel and express at will. By the time a girl reaches her tweens no one bats an eye when she screams at the sight of an insect.

When girls become women, this fear manifests as deference and timid decision making. We try to counter this conditioning by urging ourselves to “lean in.” Books on female empowerment proliferate on our shelves. I admire what these writers are trying to do — but they come far too late.

We must chuck the insidious language of fear (Be careful! That’s too scary!) and instead use the same terms we offer boys, of bravery and resilience. We need to embolden girls to master skills that at first appear difficult, even dangerous. And it’s not cute when a 10-year-old girl screeches, “I’m too scared.”

When I worked as a firefighter, I was often scared. Of course I was. So were the men. But fear wasn’t a reason to quit. I put my fear where it belonged, behind my feelings of focus, confidence and courage. Then I headed, with my crew, into the burning building.