PORTLAND, Ore. -- A local mother says her 11-year-old son was exposed to inappropriate pictures online while he was at his southeast Portland school.

Melinda Cobb said her son, a student at Hosford Middle School, was in a behavioral classroom Thursday when he saw another student looking up sex pictures online using Google Images and YouTube.

The school notified her about the incident, Cobb said, but she's concerned other students could gain access to sexually explicit pictures.

"I've complained about this before. This is just the most inappropriate situation so far," Cobb said. "They should have parental control of some sort. I mean, school computers should be for educational purposes."

Portland Public School District officials said they have a strict Internet policy, but no filter system is 100 percent effective.

School computers don't allow access to certain Web sites, officials said, but Google and YouTube aren't blocked.

The district's policy on student Internet use says, "In the event there is an allegation that a student has violated the Acceptable Use Regulation, the student will be provided with a written notice of the alleged violation and an opportunity to present an explanation before a district administrator."

Cobb said she's told her son not use the school computers until the district changes what students can find online.

"I take all the precautions at home on my own to make sure that my child isn't exposed to things that he, for one, shouldn't be exposed to," she said.

Son Saw Sex Pictures At School, Mother Says