Context: The Internet has become an important tool for finding health information, especially among adolescents. Many computers have software designed to block access to Internet pornography. Because pornography-blocking software cannot perfectly discriminate between pornographic and nonpornographic Web sites, such products may block access to health information sites, particularly those related to sexuality.
Objective: To quantify the extent to which pornography-blocking software used in schools and libraries limits access to health information Web sites.
Design and setting: In a simulation of adolescent Internet searching, we compiled search results from 24 health information searches (n = 3206) and 6 pornography searches (n = 781). We then classified the content of each site as either health information (n = 2467), pornography (n = 516), or other (n = 1004). We also compiled a list of top teen health information sites (n = 586). We then tested 6 blocking products commonly used in schools and libraries and 1 blocking product used on home computers, each at 2 or 3 levels of blocking restrictiveness.
Main outcome measure: Rates of health information and pornography blocking.
Results: At the least restrictive blocking setting, configured to block only pornography, the products blocked a mean of only 1.4% of health information sites. The differences between blocking products was small (range, 0.6%-2.3%). However, about 10% of health sites found using some search terms related to sexuality (eg, safe sex, condoms) and homosexuality (eg, gay) were blocked. The mean pornography blocking rate was 87% (range, 84%-90%). At moderate settings, the mean blocking rate was 5% for health information and 90% for pornography. At the most restrictive settings, health information blocking increased substantially (24%), but pornography blocking was only slightly higher (91%).
Conclusions: Blocking settings have a greater impact than choice of blocking product on frequency of health information blocking. At their least restrictive settings, overblocking of general health information poses a relatively minor impediment. However, searches on some terms related to sexuality led to substantially more health information blocking. More restrictive blocking configurations blocked pornography only slightly more, but substantially increased blocking of health information sites.