The reason why an individual might feel compelled to express their femininity or masculinity can vary greatly from person to person. Traditionally, gender expression has been seen as an important aspect of social identity, helping to define an individual's role and place within a given social group. For example, displaying masculine traits such as strength, assertiveness, and ambition may be seen as desirable in a context where men are expected to be the primary providers and protectors. Conversely, displaying feminine traits such as gentleness, nurturing, and sensitivity may be seen as desirable in a context where women are expected to be caregivers and nurturers.

However, it's worth noting that gender expression isn't always about fulfilling social expectations or conforming to a particular role. For many people, expressing their femininity or masculinity is simply a way of feeling more authentic and true to themselves. Some people feel a strong sense of affinity with a particular gender identity, even if it doesn't align with their biological sex characteristics or societal expectations. In these cases, expressing their gender identity is not so much about fulfilling a role, but about being true to their inner selves.