Promoting Diversity of D&D Characters

I want to promote diversity in D&D. I underestimated the controversy surrounding this topic.
That is why I propose small practical changes for D&D.

Types of Character Discriminations in D&D

In my opinion, D&D needs more diversity and I cover different types of discrimination and practical ways to improve diversity.
I'm only going to cover types of discrimination that I've got something useful to say about: gender, age, disability and sexual orientation.

Discrimination in D&D Societies and Settings

Discrimination in D&D depends on the societies and the settings in which people are playing.
I list my expectations for historical settings and the default D&D setting.
Small changes in settings have a large impact on the diversity of settings.

In the previous post I talked about discrimination in D&D writing.
I looked into the player's handbooks for D&D 4E and found that some societies in the core books have different gender roles.
I want to see what impact a setting has on discrimination.

Discrimination in D&D 4E Writing

I want more diversity in the D&D games I play in, mostly after reading about sexist art in D&D.
Although diversity can fixed by the DM, it's a lot easier if the core books and adventures fully support it, as a good example to new and experienced DMs.