I read that in Western countries, people prefer their first name over their family name, that is why they put their first name first, in form first name + family name For example Wayne Rooney, Steven Gerrard, ...
This is contradicts with Eastern countries, where people full name is of form family name + first name
But in Football (or Soccer in America), you can see in the uniform that they use their family name only. For example Rooney, Gerrard, ...
Why is that?