Opposition to increasing the minimum wage is often based on a false idea of who gets it. It’s seen as an entry-level pay scale for teenagers who soon make more as they acquire skills. It’s just pocket money for gas and hamburgers, the argument goes, and it needs to stay low so youngsters can get an opportunity to learn about working.

While that may have been true in the past, it’s not now. Minimum wage earners are older than before, more likely to be supporting children and the average minimum wage worker brings home half or more of her family’s income.

An increase in the national minimum wage is long overdue, but dysfunction in Washington has pushed the issue onto the states. Maine has not given its lowest paid workers a cost of living increase since 2007, and whether it will do so next year will depend on the outcome of the elections for the Legislature and governor.

The city of Portland is right not to wait. Housing costs in Maine’s largest city are among the highest in the state, and it makes sense for workers here to get relief first. If Congress and the Legislature won’t act, the city should.

This week, Portland Mayor Michael Brennan held a forum on his plan to increase the minimum wage in the city from $7.50 to $9.50 next year. The plan calls for subsequent increases to $10.10 and $10.68 in the next two years, and indexing it to inflation after that. Workers who receive tips would be paid at an hourly rate that’s half the new minimum wage.

The idea has been criticized by some business interests, who, among other things, argue that this would primarily benefit teenagers who don’t need the money.

But this is not true, according to research done by the Economic Policy Institute and the Congressional Budget Office.

Of workers earning minimum wage nationally, 88 percent are at least 20 years old; half are older than 30; and about a third are 40-plus.

More than half (54 percent) of minimum wage earners work full time, and another 32 percent work at least half time, showing that these are not just after-school jobs. More than a quarter of minimum wage earners are parents, and 19 percent of all children would benefit from an increase in the national minimum wage.

Women, who make up 48 percent of the workforce, have 55 percent of the minimum wage jobs, making the current minimum wage a not-so-hidden form of sex discrimination.

This debate comes as wage growth is stagnant, despite a recovery now in its seventh year. Prices go up, rents go up and utility costs go up, but many low-wage workers have had their pay frozen.

There are small businesses that do hire teenagers, and teach them what is expected of them on the job. That is a very important role, and it’s reasonable to ask the state government to help them continue to do that service. But holding down wages for low-income families on the edge of poverty is the wrong way of accomplishing that goal.

Raising the minimum wage is a pro-family policy that rewards hard work and circulates money in the local economy. It’s also the right thing to do. Portland should not wait for Congress to figure that out, and should take this long overdue step.