The Howard County Board of Education, weaving together two years of work by educators and parents, has completed a plan to expand its family-life and sex-education curriculum while avoiding the rancor that has marked similar moves in other Maryland counties.

"I won't say that everyone is 100 percent happy with the revised program, but there's really no loud objection to it," said Ronald E. Elwell, the Howard education official who oversaw the work of three countywide advisory committees on sex education in elementary, middle and high schools.

The plan, set for a vote by the board tonight, has the most dramatic effect on the county's family-life and human-development course for fifth graders, which was first adopted in 1971. It calls for a new filmstrip on puberty for fifth-grade boys called "Puberty: From Boy to Man," new slides on the female reproductive system for girls' classes, and a 12-page booklet called "Just For You" for all children in the seven-hour course.

The booklet, which outlines the way the body changes between the ages of 10 and 12, also includes crossword puzzles on the reproductive systems.

"I have no qualms about this curriculum," said Marilyn Gilliece, who represented an Ellicott City elementary school on the advisory panel and whose daughter, a fourth-grader, will one day be taking the course. "We've done what's best for the children."

Unlike Montgomery and other counties where family-life programs have sparked periodic feuds between school boards and parents, Howard was able to avoid divisive debates by painstaking reviews of course material and a series of community meetings with parents, officials and parents said. A 20-member group of educators and parents, who worked on the proposals for fifth-graders, included parents from both the conservative and liberal parts of the county.

Parents were able to review course materials at a series of "family-life nights." They also have the option of excluding their children from the fifth grade course.

"We've done without a lot of the hostility and polarization . . . by making that option very explicit," said school board chairman John Murphy.

"This touches on individual values in a very intimate way," Murphy said. "Our secret has been a willingness to open up the process to parents."

The advisory committee for Howard high schools recommended virtually no changes to that curriculum; the middle school panel, meanwhile, proposed only the addition of a book called "Family Living and Human Reproduction."