Time flies when your baby is growing up happy and healthy despite a congenital heart defect, and you're battling Congress to make sure kids like him aren't cast out as uninsurable.

It does not seem like it's been six months since late-show host Jimmy Kimmel tearfully told his audience that his newborn son had to undergo life-saving heart surgery.

But it's true, as he pointed out with a new photo of a beaming Billy, who turned six months old Saturday.

Billy was diagnosed with Tetralogy of Fallot with pulmonary atresia, a combo pack of four related heart defects, within hours of his birth on April 21.

Doctors at Children's Hospital Los Angeles immediately dealt with the most pressing problem: Repairing an obstructed pulmonary valve, so that blood could reach his lungs to be reoxygenated.

Kimmel has not said whether Billy has undergone a second surgery to repair the hole between his left and right ventricle.

That procedure, which prevents oxygenated blood intended for the rest of the body from spilling back into the ventricle it just left, typically happens by the time the child reaches the six-month mark.

Spurred to action by Billy's case, Kimmel has been holding politicians' feet to the fire, insisting that any Obamacare replacement preserve protections for patients with pre-existing conditions.

Last month, he went after Sen. Bill Cassidy (R-La.) for renegeing on his promise that any new bill up for consideration would have to pass the "Jimmy Kimmel test."

"Unfortunately, and puzzlingly, he proposed a bill that would allow states to do all the things he said he would not let them do," Kimmel told his audience, adding that "he made a total about-face, which means he either doesn't understand his own bill, or he lied to me."