Homophobia.

Who's up for International Day Against Homophobia? (Monday, May 17th)
All you have to do is wear a plain black shirt to silently protest homophobia. If you can, you can write "Gay rights are human rights" on your arm or on a piece of clothing.
*definition* Homophobia: The fear of homosexual behavior and those who practice it, often manifested as hate.
And by behavior, I mean everything, including kissing, holding hands, and the simple act of loving. (I know, loving can be anything but simple. But falling in love can be easy.)
This might not be the best definition. But I think it's the closest. Remember that post about labels? I would wager that homophobia is mostly about fear of the unspoken 'rules' getting broken.
I think that transphobia takes a slightly different definition than homophobia, but for simplification, assume that trans-phobia is included in, but not the same as, homophobia.
Transphobia: The fear of behavior and dress as though one were the opposite sex (especially in M2F trans people), often manifested as hate.
Homophobia is a horrible thing. It makes people fear themselves, their friends, and their family in the name of 'what's right'.
It is not a disease to be GLBTQ. Be proud.

Stop Labeling

We are all forced into labels and categories, and we don’t always notice. Rich. Poor. Young. Old. Blonde. Brunette. White. Black. Catholic. Buddhist. English. Hispanic. And dozens of others. But the least obvious categories are Girls and Boys. They can be called other things, like Females and Males, or Women and Men, Chicks and Dudes, Dolls and Guys.

The Girl has only female organs, is attracted only to boys, and (less commonly accepted) plays ‘house’ or with dolls, is docile, subservient, good in the household, unable to lead, and less able than the Boy.

The Boy has only male organs, is attracted only to girls, and (again less commonly accepted) is dominant, a capable leader and a good example, is above household duties except physically difficult tasks like mowing the lawn, and more able than the Girl.

I think the biggest problem people have with GLBTQ people is that they break those boundaries.

Intersex and transsexuals have physical makeup that breaks the boundaries. Gay, bisexual, and most especially labelless people break the boundaries of attraction. Femme and butch people of the opposite sex (not to mention capable women and type B men) break the boundaries of what is appropriate to enjoy, be good at, ‘Gay’ has become a separate category, but even it has its rules, like attracted only to the same sex and is either resembling the opposite sex, or is ‘with’ someone like that.

That would be a good final goal: For there to be no labels. For people not to have to come out, but for guys to be able to say, "I'm dating this great guy" or "I used to have this great game I played with dolls" (and vice versa for girls) without anybody batting an eye. I don't know that that'll happen in my lifetime, but it would be nice to hope.