The justice league (TAS the animated series version)

Are all at the watchtower Talking when all of a sudden a portal opens and something is thrown through, Superman reacts fast enough and noticed that it was a baby that was thrown through so he catches the baby as gently as possible, as all the heros try to run to the portal but it closed before they Could get near it. 

They all turn to superman to see him cradling a small blanket and when they ask what it is they are all shocked to learn it is a baby girl.

They start trying to work hoe a baby was sent to them when all of a sudden the baby Bursts into flames.

Shocking every one who panic thinking the baby is hurt badly but are surprised to see that The baby doesn't even notice she is on fire.

After batman runs a few tests it is discovered that the baby girl is only a couple months old and is A meta human.

They know that they can't leave the baby girl at an orphanage so they try to come up with an idea, Wonder Woman is the one who comes up with the idea for all of them to raise the baby in the watchtower, as no one can look after they baby themselves and she would be safe in the watch tower.

Weeks go by and the league has grown  extremly fond of they baby girl, they have a vote to choose a name(you choose name)

Months go by and c/n (child's name) has become a daughter to the league.

The only real problem they have is that she bursts into flames at the most random of times and nothing can extinguish her.

Years go by and c/n has grown Into a young girl with personality traits from the whole team.