Most moms want their newborns to be tested for fragile X syndrome, but a significant number of parents remain reluctant to find out if their children have the disability, new research suggests.

In a study of more 2,000 mothers in North Carolina, researchers asked why they did or did not agree to have their newborns screened for the FMR1 gene, which is responsible for fragile X.

Overall, nearly two out of three parents agreed to have their babies tested. Black mothers were least likely to consent to the screening while those with graduate degrees were more likely than parents with only a high school diploma to consent, according to the study published this week in the journal Pediatrics.

Most who agreed to have their children tested said they did so because the wanted “to know.” But among those who declined the screening the reasons varied, with some saying they didn’t want to worry or preferred not to know and others expressing negative opinions about genetic testing.

Currently, many children are not diagnosed with fragile X until age 3 even though the condition can be flagged earlier. With that in mind, some in the medical and advocacy communities believe that establishing more uniform testing for fragile X in newborns would allow those affected by the disorder to obtain information sooner.

Given that there is no cure for fragile X and that not everyone with the gene ultimately has the disability, the researchers said they were not surprised that only about two-thirds of parents agreed to testing.

Aside from implications for fragile X, those behind the study said the findings shed light on whether or not parents are open to testing for any condition where there is no cure as debate continues over which screenings should and should not be mandatory for newborns.