As summer vacation begins, 17 girls at Gloucester High School are expecting babies?more than four times the number of pregnancies the 1,200-student school had last year. Some adults dismissed the statistic as a blip. Others blamed hit movies like Juno and Knocked Up for glamorizing young unwed mothers. But principal Joseph Sullivan knows at least part of the reason there's been such a spike in teen pregnancies in this Massachusetts fishing town. School officials started looking into the matter as early as October after an unusual number of girls began filing into the school clinic to find out if they were pregnant. By May, several students had returned multiple times to get pregnancy tests, and on hearing the results, "some girls seemed more upset when they weren't pregnant than when they were," Sullivan says. All it took was a few simple questions before nearly half the expecting students, none older than 16, confessed to making a pact to get pregnant and raise their babies together. Then the story got worse. "We found out one of the fathers is a 24-year-old homeless guy," the principal says, shaking his head.