My favourite post of last year lists what you need to know if you are expecting a boy. In short they are messy, muddy, and obsessed with collecting sticks. I put the latter down to primal instincts regarding the need for fire. As far as I can tell, boys aren't as emotionally complicated as girls. They will randomly play with others in the park. There is no need to even know their name. It will often involve racing, finding sticks or a ball. What you see is what you get. There is no hidden meaning to anything. As long as you keep them fed and watered they are happy. I believe that the collective term is a bundle of boys.