Our governor is a master of the grand gesture.

This week, as the old year closed, Andrew Cuomo granted conditional pardons to more than 100 New Yorkers who had been convicted of crimes when they were 16 or 17.

New Yorkers convicted or incarcerated at those tender ages are invited to apply through the governor’s website; each will be screened and must meet certain criteria. At least 10 years must have passed since the conviction of a misdemeanor or nonviolent felony, and no other convictions can have occurred since. Those convicted of a sex offense aren’t eligible.

The person must live in New York State, be up to date on taxes, and be a productive member of society — working, looking for work, in school, or legitimately unable to work.

Those who are pardoned will no longer have to deal with the stigma of a conviction on their record; they will have a second chance.

We applaud this gesture. But it is just that — a gesture.

The root of the problem remains. Adolescents at age 16 and 17 should not be treated as adults. An arrest in Guilderland last month vividly illustrates the arbitrariness of the law.

After Guilderland High School was locked down for two empty bomb threats, two students, whom police say were working together, were arrested on felony charges because of emails sent to school administrators.

The boy who is 15 is considered a juvenile under New York State law; his name is not made public and he was released to his parents with his charges to be handled in Family Court, where the records are sealed. His young life will proceed without blemish.

His friend, just two months past his 16th birthday, had his name released and appeared in Guilderland Town Court. He was arrested at his home with his parents not there and unaware of his arrest. His arrest record and conviction, if any, will remain public.

For over 16 years, we have written in this space, that adolescents under age 18 should not be considered adults under the law. New York and North Carolina are the only two states that prosecute and jail 16- and 17-year-olds like adults.

Criminal defense attorneys have long argued that an adolescent’s brain is different from the brain of an adult or a child. Now there is research to prove it.

“Brain research — and even brain-imaging technology — has had an impact in changing people’s views,” said Elizabeth S. Scott, a Columbia professor and co-author of “Rethinking Juvenile Justice,” in a Columbia Law School Magazine article. “There’s something about colorful pictures of the brain that seems to impress people. When they can actually see the differences in adolescent brains, they can believe it.”

We looked at such magnetic resonance images, taken by Paul Thompson of the UCLA School of Medicine and published in Harvard Magazine. They showed human brain development between the ages of 5 and 20: Gray matter (shown in red) grew and then, with the onset of puberty, gradually decreased. Scientists say that cognitive abilities improve as gray matter thins, as the brain pares redundant connections and benefits from increases in the white matter that helps brain cells communicate.

Harvard neurologists Frances Jensen and David Urion have found that the brain is only about 80 percent developed in adolescents. The cortex, the brain’s largest part, is divided into lobes that mature from back to front. The last section to connect is the frontal lobe, responsible for cognitive processes such as reasoning, planning, and judgment.

“The idea is,” said Scott, “because of their immature brains, adolescents may be more likely to engage in reckless and sensation-seeking behavior — and to get involved in criminal activity.”

Scott studied the matter as part of the MacArthur Foundation Research Network. Its director, Dr. Lawrence Steinberg, reported, “The Network set out to find scientific evidence of whether juveniles were different enough from adults to merit different treatment by the courts. What we found was that young offenders are significantly unlike adults in ways that matter a great deal for effective treatment, appropriate punishment, and delinquency prevention. Society needs a system that understands kids’ capacities and limits, and that punishes them in developmentally appropriate ways.”

Most states recognize this. About half have juvenile justice systems. Juvenile justice systems, according to the Office of Juvenile Justice and Delinquency, have rehabilitation and treatment at their core rather than solely punishment. Also, limitations are placed on public access to juvenile records because of the belief that juvenile offenders can be successfully rehabilitated and to avoid their unnecessary stigmatization.

Further, the juvenile justice system follows a psychological casework approach, taking into account a detailed assessment of the youth’s history in order to meet his or her specific needs.

In 2012, the United States Attorney General’s Task Force Report on Children Exposed to Violent Crime stated, “We should stop treating juvenile offenders as if they were adults, prosecuting them as adults in adult courts, incarcerating them as adults, and sentencing them to harsh punishments that ignore their capacity to grow.”

Also in 2012, Jonathan Lippman, then the chief judge of the state of New York, outlined in his “State of the Judiciary,” a plan to “change the way the justice system responds to 16- and 17-year-olds accused of nonviolent crimes.” He estimated as many as 50,000 youths that age are arrested and prosecuted in New York, overwhelmingly for minor crimes.

“Our statute is a relic,” Lippman said, “the product of disagreement in the Legislature when the Family Court was created in 1962. The intent was always to study and revisit the issue. But here we are, 50 years later, with the ‘temporary’ fix still in place — to the detriment of our most precious asset, our children.”

He also said, “Study after study has confirmed that older adolescents who are prosecuted and convicted in criminal courts are more likely to re-offend, re-offend sooner, and go on to commit serious crimes at a higher rate than youths who go through the family court system. Prosecuting adolescents charged with nonviolent conduct in the criminal courts does not improve public safety or the quality of life in our communities.”

It’s important to note a juvenile justice system would not only improve the lives of adolescent offenders but would help society as a whole.

Lippman proposed a system that would put “first and foremost an emphasis on rehabilitation for adolescents, rather than incarceration,” stating, “The present punitive approach turns children into hardened criminals and must be changed if we are to ensure a meaningful future for kids who find themselves in the throes of the justice system.”

Governor Cuomo has made some progress through executive actions but he needs backing for his 2015 legislative initiative, dubbed Raise the Age.

Last year, through executive action, Cuomo removed minors from adult state prisons where they are likely to be victimized and learn criminal behavior. Data from the state’s Division of Criminal Justice Services and the United States Department of Justice, show that youth housed in adult facilities are five times more likely to be sexually assaulted, two times more likely to be injured by prison staff, and eight times more likely to commit suicide than their peers in juvenile facilities.

The vast majority of the 16- and 17-year-olds in New York prisons and jails are incarcerated for nonviolent offenses.

Under Cuomo’s executive action, all male youths needing minimum or medium security and all female youths have been transferred to the Hudson Correctional Facility where staff has been trained to develop youth-based programs.

But the legislature needs to take the next step to make 18 the age for adult treatment under the law and to seal crimes committed at a young age after a person has remained crime-free.

Young offenders deserve a chance to right their wrongs and go on to lead productive lives. Society as a whole will benefit in the long run.

We in no way condone school bomb threats — they are wrong, costly, and hurtful — but, as New York State is belated in the process of recognizing what brain research clearly shows, we urge the criminal justice system to take that into account as the Guilderland High School bomb-threat case proceeds.

The punishment should fit the crime — and it should fit the mind of a young perpetrator.

Editor’s note: The editor’s husband is the spokesman for the New York State Court of Appeals.