CHICAGO (CBS) — One age doesn’t fit all – that’s what dozens of Chicago parents say about the Chicago Public Schools’ rigid policy about starting kindergarten at age five and no later.

CBS 2’s Dana Kozlov reports that some parents are challenging that policy, especially when it involves children with special needs.

Five-year-old Yannick Koch is adjusting to life in kindergarten at his Chicago public school, but it’s an adjustment his parents didn’t want him to have to make yet.

“The universal consensus was … he would really benefit from another year of preschool and go into kindergarten at six,” his mother Holly Karris said.

That’s because Yannick was born premature, had medical complications and, to this day, is developmentally delayed in several areas.

But his mother asked CPS to delay Yannick’s kindergarten start, officials gave her a firm no. The policy doesn’t allow it.

“It’s a terrible policy. It’s a terrible … it’s just so hard on kids. It’s not the way to do things,” Karris said.

Stephanie Salerno is in a similar struggle regarding her 5-year-old son Aidan.

So she’s decided to keep him out of kindergarten, rather than enrolling him at the age of 5.

“He wasn’t ready and I was concerned that he wouldn’t be successful,” Salerno said. “I thought it was better to keep him in a program where he could learn more and be successful so that it would give him another year before he could enter school.”

Again, the reasons for wanting to wait until he turns 6 to send Aidan to kindergarten were because of developmental delays and a possible Asperger’s syndrome diagnosis. Salerno was also told there’s no flexibility with the CPS policy.

“I don’t’ agree with it, because I think for children with a (developmental disability) diagnosis, they should look more at their developmental age … than the actual birthday,” she said.

Therapist Lorrell Marin said, “There’s lots of things that go behind them being prepared for school, like their social/emotional development.”

Therapists like Marin say that, with some flexibility, everyone wins.

“To have a child get that extra year to develop so that they can be successful in the classroom would be beneficial for the other children, for the teachers and the entire school,” Marin said.

Marin and parents said that principals used to have some discretion about the age for starting kindergarten, but not anymore.

No one with CPS would go on camera and would not say why the policy is now so rigid. But, in a statement, CPS officials said the district is now reviewing the policy. Officials also said that the issue of age-appropriate enrollment for young children is critical and they are committed to working with families to find reasonable solutions.