Can a kiss determine compatibility?

A single kiss probably won’t reveal your compatibility with someone. If it’s the first time you’ve kissed, there might be some nerves or awkwardness involved, and this doesn’t mean that you won’t build more physical compatibility as you get more comfortable with each other. On the flip side, the way you feel about kissing someone over a longer period of time could be more revealing. If you’ve been dating someone for awhile and you don’t really enjoy kissing them, this could mean you don’t have physical chemistry.

A kiss alone doesn't determine your compatibility. Physical compatibility is more about having the same attitudes and expectations about what sex represents in your relationship.