WASHINGTON - Connor Geddes was 13 days old when surgeons gave him a new heart that didn't match his blood type - deliberately.

Connor, now 11 months old and thriving, is one of several dozen babies around the world to have received mismatched hearts, part of a slowly growing movement to increase these tiniest patients' survival by taking advantage of a lag in their immune systems.

Now the nation's transplant network is expanding that effort, saying youngsters may be candidates for an incompatible heart up to age 2.

It's the first step in a new push by the United Network for Organ Sharing to decrease the number of children who die awaiting an organ transplant, a toll particularly high for infants and toddlers.