Chicago ? More than a decade after it began, take-your-kid-to-work day appears to be losing steam. Now it’s keep-your-kid-in-school.

Thursday marked the 17th year for Take Your Daughters and Sons to Work Day. But some school districts sent strongly worded letters or e-mails to parents explaining that taking a child to work would put the youngster’s education at risk.

Many teachers found their Thursday classes largely unaffected.

“We had only six out today — that’s actually less than usual,” said Darrell Propst, principal of Taylor Road Elementary School in Reynoldsburg, Ohio, who asked parents not to pull their kids out of school. “Our attendance was very, very good today.”

Though many kids still accompany a parent to work, some employers say the event increasingly conflicts with high-stakes standardized testing in schools. And this year, it was overshadowed by Earth Day, which celebrated its 40th anniversary on Thursday.