If you touch another boys penis are you gay?

That would depend.. If you liked it, then you most likely are. If you didn't enjoy it, then you're probably not.

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Alternate

The above is one point of view. Children (we do not know the questioner's age) will often experiment, and it is unreasonable to conclude that juvenile behavior like that described indicates an over-all life-long orientation, even if it is enjoyed. Of course, the young person may in fact be gay, but that is very far from certain. There is no need for young people to have anxiety or stress over this. Don't be concerned about this if you have done it, and allow yourself to grow up and interact with all of your friends. Sometimes even young men into their college years and beyond will have periods of experimentation with sexual orientation, and they go on to have lives as ordinary heterosexual guys without desiring to return to gay activities.

On the other hand, if patterns develop and continue into your adult life, then the likelihood that you are sexually attracted to men increases. If it's true and you come to a full awareness of it, that is very cool. That would not mean that you are not also attracted to women. Sexual orientation is a complex thing, and only many years of growing up will bring you to a clearer picture of what's going on with you. Relax, and enjoy all of your friends. And enjoy growing up, to the degree that anybody can.