When her elementary-school classmates passed out cards, she got a few--but her twin sister, Joan, always got more. And while Jane received cheap dime-store greetings, the boys in her class saved their allowances to buy "special" cards trimmed with ribbon and lace for the more popular twin.

Nearly 40 years later, the memories are still fresh. "One boy bought her a big, red plastic heart pin," says Yeomans, 47, of Scranton, Pennsylvania. "I was so jealous, I used to go look at it in her jewelry box all the time."

Valentine's Day is supposed to be a day of love and friendship. But for many children, it is also a day of social reckoning--a measure of their likability so powerful that, as Yeomans can attest, the sadness lingers long after the cards have been thrown away. Such feelings are intensified by the fishbowl environment of most schools, where children build their first social networks and learn to cope with people outside their own families.

"Kids want to feel they're as good as--or better than--other kids, and one of the ways they do that is by comparing themselves to the members of their peer group," says Dr. Glenn Hirsch, deputy director of child and adolescent psychiatry at New York University Medical Center in New York City. "They're always looking to see who got the better grade, who does better in gym class, who's the most popular socially."

The ritual of exchanging valentines becomes one more measure of self-worth and turns countless children into heartbreak kids. Getting fewer than your classmates, Hirsch says, sends a stark message that "you're not as lovable."

Laura Muha, who has written for GOOD HOUSEKEEPING and REDBOOK, always got a "medium number" of valentines.