Of course we're all different, so maybe your son is more introverted or quiet or reflective. But:

- Outside of family, it's likely your son received LOTS of messages (both explicit and implicit) about "being a man" and controlling his own emotions.

- Even when parents are sure of raising their children in some way, there might be some instances in which they unconsciously treat each child differently (e.g. when a parent says "I have no favorite child", they often do).