Things that make a real man?

Ive noticed that with different generations the idea of what a "real man" is changes why is that? It seems that the qualities women want in their ideal man are the simple values that your parents teach you. One of my friends made this comment to me the other day saying that I was a "real man" (im only 19) but it made me wonder what it was about me that made her say this. The list she gave me were simple aspects id expect any good respectable person to possess. I used to think being a "real man" meant hunting or building your own house, things like that but it seems to have changed with the times. Now obvious things like being loyal, providing for your fam, and doing whats right seem to be the hallmarks of a real man. What the heck happened? What do you think the definition of a real man will be in 20 years if right now we're down to the basics?