My ears are stretched to 5/8" (16mm). I think its just a coincidence that I used to identify as a lesbian.
I started stretching my ears when i was 19, and over about 5 years got them to the size I have now. Thought about going to 3/4", but then I realized I would have to buy all new plugs, and I like the ones I have now. It kind of started as a rebellion thing, I wanted nothing to do with anything that could be considered "normal". I've since gotten over that (a long with my former crust punk wardrobe and blue hair) but I still really like how it looks. Can't really explain why, I just do.
Regarding safety, its only dangerous if you do it wrong, You have to go slowly and only 1 size at a time or you will mess up your ears. Ive seen kids try to go up a size every 2 weeks or so, or try to stretch too much at once, and it ends up looking horrible. If you don't give your skin time to recover (at LEAST 2 months) the ear lobe can tear when you try to stretch it, or areas can get too thin and weak. If theres ever blood, you've done something horribly wrong, and you will probably end up with an infection.