Then Biff watched as the man freaked out, demanding to know why he was dressed like a woman. His wife, meanwhile, thought that her husband had gone crazy. After all, he wasn't dressed like a woman ... he was dressed like a man. Men were the ones who wore dresses, obviously.
It seemed that whatever was happening, people who were male were able to notice that things were different, while people who were female thought the "gender role reversal" was how it was always supposed to be.
But Biff, Sarah, and that married couple were only the first to be changed. Like a wave, the changes continued, slowly expanding outward from Biff himself, until eventually, all of Lake Point would be affected.