One of the casualties of the "sexist" movement was a boy's identification as a man. We are so scared to sound sexist that we work especially hard to not support or distinguish the role of manhood.
Let me caveat that with the fact I feel strongly that girls should be allowed and encouraged to be able to work and play sports without discrimination.
However on the other side of that; we have ignored that young boys take pride in doing a "man's" job.
Pumping Gas is a good example - of course the girl can do it. But watch a young boy run out and pump the gas for mom with his shoulders back in a sense of pride that he's "man" enough now to do it. That reaction and attitude is a healthy thing that boys need to feel good about them selves. Don't be afraid to encourage and support your son with "man" jobs even if they are not limited to men.
A example in the BAM program is asking a young boy to take out the trash but using the phrase, "let's see you use some of those man muscles and get that big load of trash to the curb son." He'll love that recognition and react to it in a positive way.
Don't be afraid to encourage your son to be a man.