I do not have twin brother, I'm the only older brother is a terrible grump , but I like him very much
In Poland we had ever prime minister and president who were identical twins, the president sadly died in plane crash:-( , but when they ruled together, Prime Minister was an older twin, and it looked as if dominated the president.
I also have a cousin twins, girls, looks like that one that supposedly is older was a little more dominant. I wonder if there are reverse situations.