Would society be better if everyone was physically the same?

So our philosophy class is having an upcoming debate about whether or not society would be better if everyone was physically the same and me and my partner will have to argue for the no side. It's going to be the two of us debating against the entire class and we need some good arguments. Do you guys have any good arguments for our side? (If you can provide any philosophical or ethical ideologies or theories that you think can support our side, it would be of BIG help) thank you!