One of my friends says it does. That seems insanely broken to me. I don't want to waste two great persons testing this. Anyone know ?

It does not affect the other members of a team. When one person in the team gets a golden age, it only affects them. I know this because in a team pbem with my brother (where we are on the same team against AI's), I built the Taj Mahal and got a Golden Age. He didn't.