Which sociological perspective would highlight the reluctance among professional athletes to display any sexual identity other than heterosexuality in public?

Answer is queer theory.

Explanation:

Queer theory is a theory that was formulated towards the sexual minorities. These sexual minorities are those with the act of having sexual relationship with the people of their gender or sex. This is called homosexuality.

This theory portray them as abnormal or strange people in the society, thus making them to hide their sexual identity.

In this sense, professional athletes normally display heterosexuality as their sexual identity to avoid this notion of queer theory.

Note that, heterosexuality is the sexual attraction or behavior to the person of opposite sex, e. g sexual attraction between a man and a woman.