Two groups filed a federal lawsuit Tuesday to block a health curriculum that would allow discussions of homosexuality with eighth-graders and a video to be shown to sophomores demonstrating how to use a condom.

Citizens for a Responsible Curriculum (search) and the Virginia-based Parents and Friends of Ex-Gays and Gays want to prevent Montgomery County (search) from starting the program in six schools later this week. A hearing has been set for Thursday.

The new program, approved by the county board of education in November, would be used in all schools next year.

Parents must sign permission forms for their children to take part in the health curriculum and parents can sit in on the sessions. Families also can choose alternatives that include abstinence-only programs.

County educators say the changes were needed to teach students about the dangers of unprotected sex. However, those suing argue the county does not do enough to stress abstinence or allow people the groups describe as formerly gay to present their views.