In recent years, as people’s weight has ballooned, breasts (mostly made up of fat) have only gotten larger, and commensurately bra cup sizes, too. K-cups now exist. Brandishing a tiny bosom may be a reaction to that trend.

Unlike many women who struggled as teenagers to make peace with their minimal assets, Sabrina Lightbourn, 37, a photographer in Nassau, the Bahamas, never second-guessed her A-cups, even in a land of bikinis. “In my mind, they are fabulous,” she said. Sometimes, she favors down-to-the-sternum cuts that make it “really obvious that you don’t have much.”

Small-breasted women have also begun to express their anger on the Internet when they suspect one of their brethren has decided to artificially augment what nature has given her. This year, pictures of a bikini-clad Kate Hudson  along with Keira Knightley a symbol of modest-breasted seductiveness to the A-cup population  surfaced showing what looked like modest implants. Afterward, Jen Udan, who works in Internet marketing in Austin, Tex., felt as if she had been slapped in the face. “I don’t need to look up to you, Kate Hudson,” Ms. Udan, 25, wrote in a blog post entitled “Diary of a Mad, Small-Breasted Woman.”