More than half of American families with teenagers use filters to limit access to potentially harmful online content -- a 65 percent increase from the number of those who used filters in 2000. But big majorities of both teens and parents believe that teens do things on the Internet that their parents would not approve of.

A new survey of 1,100 youth -- those ages 12 to 17 -- and 1,100 of their parents shows that 54 percent of Internet-connected families now use some sort of Internet filter or monitoring software, up from 41 percent of Internet-connected families who used filters in 2000, the most recent time the Pew Internet & American Life Project surveyed on the issue. In all, about 19 million youth live in homes with Internet connections and the number of children living in homes with filters has grown from 7 million in 2000 to 12 million today.

The filters tend to be used by parents who themselves are frequent users of the Internet and who have middle-school-age children. Parents who have older children and who are less tech-savvy are less likely to use filters.

At the same time, parents are showing higher levels of vigilance about protecting their children online, there is striking consensus among parents and their teens that the teenage population is not as careful as it should be online and that teens do things online their parents don't know about.

• 81 percent of parents of online teens say that teens aren't careful enough when giving out information about themselves online and 79 percent of online teens agree with this.


• 65 percent of all parents and 64 percent of all teens say that teens do things online that they wouldn't want their parents to know about.

"The age-old struggle between parents who want to protect their children and teens who want to assert their independence and venture into 'forbidden' realms is playing out in new ways online," said Amanda Lenhart, research specialist who wrote the Pew Internet Project's new report, "Protecting Teens Online." "Both sides agree that no matter how hard parents try, online teens are going to do things they know their parents won't like and that many will be a bit too careless about what they disclose online."

The findings also come at a time when a federal court is about to consider a lawsuit against the federal Child Online Protection Act (COPA), which was passed in 1998. It required Web sites containing "material harmful to minors" to use some kind of age verification system -- such as asking for credit card information -- to ensure that site visitors were age 18 or older. The American Civil Liberties Union and other civil rights groups sued the government, arguing that COPA is an unconstitutional infringement on the free speech and privacy rights of adults.

The case bounced through the court system until last June, when the Supreme Court ruled that the law's constitutionality should be weighed in a full trial in the federal district in Philadelphia and that the ban on enforcement should continue. It is likely that the case will begin later this year. And one of the main issues in the case is whether Internet filters can be an effective way to block access to certain Web sites and screen content.

In addition to employing filters, parents are trying other methods to stay abreast of their children's online activities.

• 73 percent of online teens say their household computer is located in a public place inside the house.


• 64 percent of parents of online teenagers say they set rules about their children's time online.

However, there are still large gaps in perception about how much parent-child monitoring is taking place: 62 percent of parents report checking up on