Marco Túlio Pacheco Coelho & Michael Gavin:

It’s uttered in hushed tones during mommy-and-me yoga classes and at Montessori-school drop-offs, discussed ad nauseam in breastfeeding support groups and on parenting message boards.

It’s called tongue tie, and it’s everywhere. In online mom groups, it’s blamed for all sorts of parenting woes. Baby isn’t gaining weight, or won’t take a bottle? Have you tried checking for ties? Kid won’t nap? It’s probably related to tongue tie. Baby have a rash? Check under the tongue!

Tongue tie, or ankyloglossia, is characterized by an overly tight lingual frenulum, the cord of tissue that anchors the tongue to the bottom of the mouth. It occurs in 4 to 11 percent of newborns. A lip tie—a related condition—is an unusually tight labial frenulum, the piece of tissue that keeps the upper lip tethered close to the gum line. Tongue and lip ties often occur in tandem.