There are some laws like this in the US. Some are state based, but some are federal...

"...a special minimum wage of $4.25 per hour applies to employees under the age of 20 during their first 90 consecutive calendar days of employment with an employer"

"Other programs that allow for payment of less than the full Federal minimum wage apply to workers with disabilities, full-time students, and student-learners employed pursuant to sub-minimum wage certificates. These programs are not limited to the employment of young workers."

https://webapps.dol.gov/elaws/faq/esa/flsa/003.htm?_ga=2.219...

I think it's certainly better than the alternative, but I would like to see minimum wage dropped for the youngest ages honestly. So much good experience could be had if the youngest and those just about to embark on their career could get some experience.

But I'm mainly interested in non-minimum wage solutions. There are even good reasons for adults to work for less than minimum wage. Think of non-volunteer tasks that a stay at home parent may be interested in working in part-time but still would like to make a modest income for.

Why wouldn’t that cause someone to discriminate against an older person?