It's a pregnant-mom rite of passage, right up there with morning sickness and sonograms: On March 27 Jamie Lynn Spears popped into a Babies "R" Us and registered for some serious baby booty. Accompanied by a female cousin, Spears, who turns 17 on April 4, drove 80 miles from her Kentwood, La., home to the nearest outpost of the baby gear mecca, in Baton Rouge. There, Spears—flashing her diamond engagement ring from her baby's father, Casey Aldridge, 18—picked out everything from teething rings at $1.49 to a $300 car seat. Within hours a dozen fake registries in Spears' name appeared online; Babies "R" Us has since launched a fraud investigation. "Her registry isn't even under her name or Casey's," says a source. Either way, local deliverymen may want to prepare themselves. The source adds, "Everything is going to get sent to her all at once."