From personal experience:

1. I am not a lesbian just because I don't want to go out with you. Perhaps I am not interested, perhaps I am interested in someone else, or perhaps I just don't like you.

2. I am not a lesbian just because I show affection towards my girlfriends. Women tend express themselves differently from men.

3. I am not a lesbian just because I seldom wear dresses or tight clothes. I choose to be comfortable over looking good.