The Importance of a Randomized Study

If you had an unlimited budget, what study would you do? I think it would probably be something experimental about changing the environment that kids grew up in. And like if you sort of moved girls and boys to a more traditional home environment, would they act differently to like a more liberal or something like that? Or trying to randomize the treatment of whatever large intervention you have between the sexes. It's really strange because many of these authors argue that the effects of these individual things are really large.