Be a man

It is not only kids who say the darndest things, adults do too. A few weeks ago, my two year old son fell while playing, I found myself telling him, common, be a man. I didn't even know when it came out of me. Then I laughed at myself. Do we expect too much from our male kids? It is understandable that the moment a girl sees her period, she is advised to keep away from boys but what does a kid who is still learning to tie his shoe laces know?
Is it wrong for boys to cry when injured, in love or heartbroken?
How tough should the average man be?