Fatal differences

“Humble yourself - as quickly as you possibly can.’’

That’s what Ronia Stewart, an Eastern Bank executive from Dorchester, has often told her son, now 19. It’s what mothers all over the country tell their black sons: If a police officer stops you, even if you know you’re in the right, say “Yes, Sir,’’ and “No, Sir.’’ Answer every question calmly.

Don’t disagree, resist, or provoke.

These mothers know from experience that being young and black can automatically make their sons figures of suspicion - that some people will take one look at them and conclude they’re up to no good. These mothers know that for young black men, there is a much smaller margin of error out there, that acting fresh or stupid, like so many adolescents do, could get their son killed.

“Our sons are not allowed to be adolescents,’’ said Monalisa Smith, a Citizens Bank executive whose son is 17. “They’re held to a different standard.’’

These mothers know that Trayvon Martin - the Florida teen shot to death by a neighborhood watch volunteer in February - and Easton student DJ Henry - shot dead by a police officer in 2010 - would probably be alive today if they were white.

Because they might have gotten the benefit of the doubt - or never been figures of suspicion in the first place.

“My son could be driving and confused about what the officer wants him to do,’’ said Smith, referring to Henry, who was shot after moving his car and hitting a police officer after he was ordered to stop. “He could be Trayvon Martin, on vacation somewhere in Florida, and approached by someone, and not know what to do in that situation. I know he would be terrified if someone was following him.’’

Smith is president of Mothers for Justice and Equality, a growing group of local women trying to stanch the violence on Boston’s streets. She warns her son about staying safe in tough neighborhoods, where he might be set upon for his sneakers.

And although he is as distant from the world of urban violence as my white 4-year-old, she must also warn him to be careful in affluent neighborhoods, too.

“If he goes in there, he could be perceived as doing something wrong,’’ Smith said.

“It may feel humiliating , but you have to teach your child to suppress that.’’

Arlene Hall, a pastor who lives in Randolph and has four sons, said she and her husband “have always felt the need to remind our boys that they are black.’’ Her 18-year-old was recently driving to a friend’s house in Braintree when he stopped to call for directions. Within minutes, three police cruisers arrived, because residents were concerned about the stranger in their neighborhood. He had been prepared for this. Three weeks earlier, he’d been riding with his father in Connecticut when police stopped their Audi for no good reason.

A few years back, Hall’s eldest son was stopped by Milton police while driving his mother’s Mercedes. The officer let him go, but not before calling Hall to confirm that her son had permission to drive the car. Each time, the men behaved the way they’d been taught: Quietly, calmly, betraying no hint of outrage.

When Sandra Stanislaus moved to Sharon with her husband and two sons, she went right to the police station to introduce them.

“I knew my children would be viewed differently because people didn’t know who they were, because of their skin,’’ said Stanislaus, a registered nurse who loves her town. “I wanted police to see that we were not strangers, we lived there.’’

And yet even with all of the rules and extra precautions, these mothers lie awake at night waiting for their sons to come home.

“You really just have to trust them into the hands of God,’’ Hall said. Because, in the end, even humility may not save them.