What sould a 13 year old boy weigh?

There is no specific limit; as your weight should reflect your body structure. What I mean is if you are tall it would make sense that you weigh more then someone half your height. Also take note, muscle weighs more than fat and muscle is healthy. I think a reasonable doctor would never tell you to stop lifting weights because you have too much muscle, although they might advise it if they believe it can/has stunted your growth spurt. The only other thing that can be unhealthy about muscle is if you gained it in an unhealthy way (ie steroids). I weigh 145 pounds, just turned 13 and I don't think I'm fat, I am rather tall with a large bone structure, and I have lots of muscle and a big bone structure. Common sense is also a good way to figure out if you are too heavy or too light. I heard a 13 year old football player died in America during or after practice, from high blood pressure; he weighed 380 pounds! obviousley he had a problem as he is double or triple most average 13 year old boys weight, I mean come on why let him play when he is so unhealthy!