( CM ) - JESSICA ALBA was bullied and branded a "slut" at school after developing her ample bosom at a young age. The actress claims the main perpetrators were classmates' mothers and her elementary school principal, who made her life misery. Writing in If I'd Known Then - a forthcoming book of essays by female celebrities - Alba writes, "The accusation still ricochets. 'They think I'm a slut?'" The pregnant star also hands out advice to troubled teens, urging them to practice safe sex: "Boys are awful. They are made of nothing by hormones until they are about 20 or 21. But it's fun to have a crush, but don't think it's forever. And use birth control and condoms, please."