No, "Infantcore" isn't some new indie-rock sub-genre. It's a roomful of babies whose movements trigger electronic sounds. It took place earlier this year at the Machine Project space in Los Angeles. Blogger doesn't let you post vimeo vids, so check it out here:
The man behind this, experimental compser Scott Cazan recently did something similar in San Francisco called Dogcore. Couldn't find any documentation of that, tho.
Baby Fab was already too old to take part in Infantcore. Hey Scott, how 'bout some Toddlercore next time, eh?