"Anything that smacks of 'girliness'—in oneself, in other boys, and, of course, by actual girls—must be concealed, ridiculed, or rejected."

Cultural messaging conditions teenage boys to be emotionally inexpressive. Vulnerability is associated with femininity, and is thus rejected by boys whose primary goal is to become a "real man."

"There is no difference at birth between boys' and girls' need for connection, nor, neurologically, in their capacity for empathy—there's actually some evidence that infant boys are the more expressive sex."

There is not a scientific, biological explanation for why boys are expected to suppress their emotions, and yet the messaging remains. While both boys and girls have a need for emotional outlets that allow them to process their feelings, only girls are given full cultural license to acknowledge and deal with their emotions.

"Emodiversity—being able to experience a broad sweep of emotions, positive as well as negative—is crucial to adults' emotional and physical health."

While emotional transparency is necessary for personal growth, boys often avoid acknowledging emotions that have to do with sorrow or fear, as these emotions imply weakness and vulnerability.