Ask them. If you are indeed their friend, it shouldn't matter to you if they are. Tell them you don't care one way or the other, you will still be their friend.
Internet
You are only gay if you find people of the same gender sexually attractive. You could even have sex with your friend, and if you did not find him sexually attractive, you would not be gay.
If you are gay with your friend, then you might be gay, or partly gay, which is called bisexual.
Not that I have been able to find.
If you like your gay friend, then you like your gay friend. That's all there is to it.
The only way to find out if he likes you is to ask him.
If by "gay" you are wondering if your friend is happy, I hope he is. It is always wonderful when you care about your friends happiness. Your friend maybe interested in same sex dating. the only way to find that out is to ask your friend personaly.
I find this question confusing, as you say you are a lesbian and your friend is gay...yet you are attracted to each other..
for one you should see how he feels about you if he does not like you that way find someone else or try to turn him gay
find a private place and take a oath/ swear your life you won't tell anyone and ask if he is gay or not and tell him if he is serious
YOu get a Gay friend the same way you get a straight friend. You be real and open.
In order to find out if he is gay, just ask. If he is a good friend he will be okay with it. Trust me...I have done it many times. If he asks you why, just say you were curious because you are interested in him.