Figuring out if someone you're dating or talking to is gay can be really confusing, especially in a world where it's generally expected that everyone will grow up to be heterosexual. It can also be difficult if they have chosen to keep it a secret for fear of bullying, harassment, or discrimination from people in their life.
When a person starts to talk about their sexuality, it's always important to listen and to let them know that they can tell you anything and that you won't judge them. However, sometimes it's easy to pick up clues about a person's sexual orientation without having to explicitly ask them.
For instance, some people have a higher-pitched voice than others. It turns out that this is partly genetic, but it can also be influenced by a person's sexuality. If a guy has a high-pitched voice, it's not uncommon to assume that they are gay.
However, there is no definitive test for sexual orientation. People can do some things that seem to indicate that they're gay, but it all comes down to what they feel and what makes them happy. Those feelings may change over time, so it's important to be open with friends and family and to respect their privacy. If you disagree with what they are saying, try to do so in a way that is respectful and does not accuse or foster hostility.