No, you can't tell for sure. You can only know for sure if that person tells you.

Lots of times, we judge people based on stereotypes. So, we assume, for example, that a gay man is going to walk and talk like a woman and a lesbian is going to act like a guy. But that’s not always true.

A guy who hates sports, but loves to cook, can be heterosexual. And, a big, burly football quarterback could be gay. You just don’t know.

Sure, stereotypes are rooted in truth. Some gay men do act feminine. And plenty of football quarterbacks are heterosexual. But there’s a danger in applying stereotypes to everyone in a particular group because many people don’t fit the stereotype.

Every person is an individual. And we’d all be better off if people treated each other with respect. If we decided to like others based on who they are, not whether they fit into a stereotype.