The editor for Yahoo! Style should head back to elementary school to learn the importance of the apostrophe:
Without the correct punctuation (and that would be two apostrophes), that headline leaves me scratching my head and dusting the dandruff off my keyboard. Were one girl’s outfits responsible for one boy’s bad grades? Or were many girls’ outfits responsible for many boys’ grades? Or was it one girl’s outfits and many boys’ grades? Or many girls’ outfits and one boy’s grades? Oy, now I’ve got a headache. I think I have to go lay down.