Here at Bridge Over Troubled Waters, Boston’s premier agency serving homeless and other vulnerable youth and young adults, we were disheartened by a discussion we heard on WBZ News on February 1. The report covered a meeting at the State House that day to discuss the “Raise the Age” bill, which would increase the legal age from 18 to 20 when young criminal defendants must be tried and sentenced in the juvenile justice system.

The bill is currently being considered by the legislature, and for many reasons has garnered strong support throughout the Commonwealth, but not so from Plymouth County District Attorney Timothy Cruz, who is against the bill.

According to comments by Mr. Cruz, who identifies himself as a “law and order” prosecutor who looks out for victims of crime, “I can join the army if I’m 18, I can vote if I’m 18, I can consent to certain medical procedures if I’m 18. But I can’t form the decision-making process to do the worst thing that’s going to destroy a family member and destroy our community?”

What the DA said is only partially true and certainly not based on the latest neuroscientific understanding of brain development that is the foundation of the bill. Age 18 is a somewhat arbitrary definition of adulthood. This is widely acknowledged, even by the US Supreme Court that noted in its landmark case (Roper v. Simmons 2005) that “qualities that distinguish juveniles from adults do not disappear when an individual turns 18.” This is one reason why there are so many discrepancies around what you suddenly can do, or still can’t do, when you turn 18.

For example, here in Massachusetts, you can’t legally drink alcohol, smoke tobacco or marijuana, or gamble until you’re 21. You can’t be a police officer or buy a gun until you’re 21. In most states you must be 20 to rent a car, and the American Academy of Pediatrics recommends that youth remain in pediatric care until at least the age of 21. Even youth in custody of DCF can continue to receive services until they’re 23.

In fact, universally acknowledged advances in neuroscience have shown that the human brain does not develop fully until age 25. Because our prefrontal cortex does not mature at least until our early to mid-20s, teens and young adults most often have an underdeveloped sense of responsibility. They act in impetuous and ill-considered ways and make questionable decisions. Their brains are malleable, they are highly vulnerable and susceptible, and strongly influenced by peers and others.

For the young people we serve at Bridge, who have experienced abuse and neglect throughout their lives, the maturing process may be delayed even longer. So no, most 18-year-olds are not always capable of making the best decisions, and that is one reason why statistically most crimes are committed by people in their late teens or early 20s.

We disagree, as well, with Mr. Cruz when he implies that raising the age for juvenile adjudication would result in coddling criminals who “do the worst thing that’s going to destroy a family member and destroy our community.” The proposed bill does not change the law pertaining to youth charged with the most serious crimes, such as first or second-degree murder. For those crimes, youth 18 or older would continue to be tried and sentenced in the adult system, as they are now. The bill also provides for a five-year implementation period so proper staffing and programming can be developed.

On the same WBZ broadcast, Jaylen Brown of the Celtics, a strong supporter of the bill, along with the Celtics organization, noted, “I think all of us in this room, including myself, were one decision away from being in a different situation.” Every day at Bridge, we see vulnerable youth who are often dismissed as surly and incorrigible blossom into successful adults and valued community members. Most of those youth were one decision away from a very different life outcome. While part of their growth is attributable to growing older, other important factors are the caring role models, support, and programming that they receive at Bridge.

Locking vulnerable, impressionable young offenders into the adult criminal justice and prison system is no justice for the youth themselves, possible victims, or the community at large. Instead, many of these young people will spend precious years when their brains and characters are being formed in a punishing and hostile environment, without the role models, support, and programs we all need to thrive. Many youth who spend time in adult prisons will return to the community angry and disheartened, with few skills, facing discrimination in housing, employment, and other important aspects of healthy living.

Instead of placing these young people in a system that is punitive and focused on retribution, deterrence, and confinement, the “Raise the Age” bill will provide an additional cohort of young people who have made mistakes and who are still in the process of growing and developing with the more supportive environment of the juvenile justice system. They will have a chance, while their character and identity are in the process of maturing, to grow into successful, contributing members of the community.